@article{lien_2019,
	title = {Electrical suppression of all nonradiative recombination pathways in monolayer semiconductors},
	volume = {364},
	url = {https://www.science.org/doi/abs/10.1126/science.aaw8053},
	doi = {10.1126/science.aaw8053},
	abstract = {Although monolayers of transition-metal dichalcogenides such as molybdenum disulfide ({MoS}2) and tungsten disulfide ({WS}2) should exhibit strong photoluminescence, in practice, defects in these materials can lead to very low quantum yields (less than 1\%). Lien et al. show that as-formed {MoS}2 and {WS}2 monolayers encapsulated in poly(methyl methacrylate) can be electrostatically doped to achieve quantum yields near unity. Under these conditions, instead of charged trion species that recombine nonradiatively, only neutral excitons that recombine emissively form. These results help explain why coating these materials with certain Lewis acids also boosts the quantum yield. Science, this issue p. 468 Electrostatic doping of {MoS}2 and {WS}2 monolayers can boost their photoluminescent quantum yield to almost unity. Defects in conventional semiconductors substantially lower the photoluminescence ({PL}) quantum yield ({QY}), a key metric of optoelectronic performance that directly dictates the maximum device efficiency. Two-dimensional transition-metal dichalcogenides ({TMDCs}), such as monolayer {MoS}2, often exhibit low {PL} {QY} for as-processed samples, which has typically been attributed to a large native defect density. We show that the {PL} {QY} of as-processed {MoS}2 and {WS}2 monolayers reaches near-unity when they are made intrinsic through electrostatic doping, without any chemical passivation. Surprisingly, neutral exciton recombination is entirely radiative even in the presence of a high native defect density. This finding enables {TMDC} monolayers for optoelectronic device applications as the stringent requirement of low defect density is eased.},
	pages = {468--471},
	number = {6439},
	journal = {Science},
	author = {Lien, Der-Hsien and Uddin, Shiekh Zia and Yeh, Matthew and Amani, Matin and Kim, Hyungjin and Ager, Joel W. and Yablonovitch, Eli and Javey, Ali},
	year = {2019},
	note = {\_eprint: https://www.science.org/doi/pdf/10.1126/science.aaw8053},
}

@article{lu_2018,
	title = {Passivating the sulfur vacancy in monolayer {MoS}2},
	volume = {6},
	issn = {2166-532X},
	url = {https://doi.org/10.1063/1.5030737},
	doi = {10.1063/1.5030737},
	abstract = {Various methods to passivate the sulfur vacancy in 2D {MoS}2 are modeled using density functional theory ({DFT}) to understand the passivation mechanism at an atomic scale. First, the organic super acid, bis(trifluoromethane)sulfonimide ({TFSI}) is a strong protonating agent, and it is experimentally found to greatly increase the photoluminescence efficiency. {DFT} simulations find that the effectiveness of passivation depends critically on the charge state and number of hydrogens donated by {TFSI} since this determines the symmetry of the defect complex. A symmetrical complex is formed by three hydrogen atoms bonding to the defect in a −1 charge state, and this gives no bandgap states and a Fermi level in the midgap. However, a charge state of +1 gives a lower symmetry complex with one state in the gap. One or two hydrogens also give complexes with gap states. Second, passivation by O2 can provide partial passivation by forming a bridge bond across the S vacancy, but it leaves a defect state in the lower bandgap. On the other hand, substitutional additions do not shift the vacancy states out of the gap.},
	pages = {066104},
	number = {6},
	journal = {APL Mater.},
	author = {Lu, Haichang and Kummel, Andrew and Robertson, John},
	year = {2018},
	note = {\_eprint: https://pubs.aip.org/aip/apm/article-pdf/doi/10.1063/1.5030737/13810425/066104\_1\_online.pdf},
}

@article{Yang.2017,
 abstract = {Here, we examine grain boundaries (GBs) with respect to non-GB regions (grain surfaces (GSs) and grain interiors (GIs)) in high-quality micrometer-sized perovskite CH3NH3PbI3 (or MAPbI3) thin films using high-resolution confocal fluorescence-lifetime imaging microscopy in conjunction with kinetic modeling of charge-transport and recombination processes. We show that, contrary to previous studies, GBs in our perovskite MAPbI3 thin films do not lead to increased recombination but that recombination in these films happens primarily in the non-GB regions (i.e., GSs or GIs). We also find that GBs in these films are not transparent to photogenerated carriers, which is likely associated with a potential barrier at GBs. Even though GBs generally display lower luminescence intensities than GSs/GIs, the lifetimes at GBs are no worse than those at GSs/GIs, further suggesting that GBs do not dominate non-radiative recombination in MAPbI3 thin films.},
 author = {Yang, Mengjin and Zeng, Yining and Li, Zhen and Kim, Dong Hoe and Jiang, Chun-Sheng and {van de Lagemaat}, Jao and Zhu, Kai},
 year = {2017},
 title = {Do Grain Boundaries Dominate Non-Radiative Recombination in CH$_3$NH$_3$PbI$_3$ Perovskite Thin Films?},
 url = {https://pubs.rsc.org/en/content/articlelanding/2017/cp/c6cp08770a},
 pages = {5043--5050},
 volume = {19},
 number = {7},
 issn = {1463-9084},
 journal = {Phys. Chem. Chem. Phys.},
 doi = {10.1039/C6CP08770A},
 file = {Yang, Zeng et al. 2017 - Do grain boundaries dominate non-radiative:Attachments/Yang, Zeng et al. 2017 - Do grain boundaries dominate non-radiative.pdf:application/pdf}
}



@article{Yan.2019,
 abstract = {Probing the exciton k-space dynamics in monolayer tungsten diselenides, Yan, Tengfei, Yu, Hongyi, Xiao, Ke, Yao, Wang, Cui, Xiaodong},
 author = {Yan, Tengfei and Yu, Hongyi and Xiao, Ke and Yao, Wang and Cui, Xiaodong},
 year = {2019},
 title = {Probing the Exciton k-Space Dynamics in Monolayer Tungsten Diselenides},
 url = {https://iopscience.iop.org/article/10.1088/2053-1583/ab0a4e},
 pages = {025035},
 volume = {6},
 number = {2},
 issn = {2053-1583},
 journal = {2D Mater.},
 doi = {10.1088/2053-1583/ab0a4e},
 file = {Yan, Yu et al. 2019 - Probing the exciton k-space dynamics:Attachments/Yan, Yu et al. 2019 - Probing the exciton k-space dynamics.pdf:application/pdf}
}

@article{Ziegler.2010,
 abstract = {SRIM is a software package concerning the Stopping and Range of Ions in Matter. Since its introduction in 1985, major upgrades are made about every six years. Currently, more than 700 scientific citations are made to SRIM every year. For SRIM-2010, the following major improvements have been made: (1) About 2800 new experimental stopping powers were added to the database, increasing it to over 28,000 stopping values. (2) Improved corrections were made for the stopping of ions in compounds. (3) New heavy ion stopping calculations have led to significant improvements on SRIM stopping accuracy. (4) A self-contained SRIM module has been included to allow SRIM stopping and range values to be controlled and read by other software applications. (5) Individual interatomic potentials have been included for all ion/atom collisions, and these potentials are now included in the SRIM package. A full catalog of stopping power plots can be downloaded at www.SRIM.org. Over 500 plots show the accuracy of the stopping and ranges produced by SRIM along with 27,000 experimental data points. References to the citations which reported the experimental data are included.},
 author = {Ziegler, James F. and Ziegler, M. D. and Biersack, J. P.},
 year = {2010},
 title = {SRIM -- The Stopping and Range of Ions in Matter (2010)},
 url = {https://www.sciencedirect.com/science/article/pii/S0168583X10001862},
 pages = {1818--1823},
 volume = {268},
 number = {11-12},
 issn = {0168-583X},
 journal = {Nucl. Instrum. Methods Phys. Res., Sect. B},
 doi = {10.1016/j.nimb.2010.02.091}
}

@article{Ma.2017,
 abstract = {Two-dimensional transition metal dichalcogenides (TMDCs) exhibit excellent optoelectronic properties. However, the large band gaps in many semiconducting TMDCs make optical absorption in the near-infrared (NIR) wavelength regime impossible, which prevents applications of these materials in optical communications. In this work, we demonstrate that Ar+ ion irradiation is a powerful post-synthesis technique to tailor the optical properties of the semiconducting tungsten disulfide (WS2) by creating S-vacancies and thus controlling material stoichiometry. First-principles calculations reveal that the S-vacancies give rise to deep states in the band gap, which determine the NIR optical absorption of the WS2 monolayer. As the density of the S-vacancies increases, the enhanced NIR linear and saturable absorption of WS2 is observed, which is explained by the results of first-principles calculations. We further demonstrate that by using the irradiated WS2 as a saturable absorber in a waveguide system, the passively Q-switched laser operations can be optimized, thus opening new avenues for tailoring the optical response of TMDCs by defect-engineering through ion irradiation.},
 author = {Ma, L. and Tan, Y. and Ghorbani-Asl, M. and Boettger, R. and Kretschmer, S. and Zhou, S. and Huang, Z. and Krasheninnikov, A. V. and Chen, F.},
 year = {2017},
 title = {Tailoring the Optical Properties of Atomically-Thin WS$_2$ via Ion Irradiation},
 url = {https://pubs.rsc.org/en/content/articlehtml/2017/nr/c7nr02025b},
 pages = {11027--11034},
 volume = {9},
 number = {31},
 journal = {Nanoscale},
 doi = {10.1039/C7NR02025B},
 file = {Ma, Tan et al. 2017 - Tailoring the optical properties:Attachments/Ma, Tan et al. 2017 - Tailoring the optical properties.pdf:application/pdf}
}



% This file was created with Citavi 6.14.0.0
@article{Robert.2016,
 abstract = {Exciton radiative lifetime in transition metal dichalcogenide monolayers},
 author = {Robert, C. and Lagarde, D. and Cadiz, F. and Wang, G. and Lassagne, B. and Amand, T. and Balocchi, A. and Renucci, P. and Tongay, S. and Urbaszek, B. and Marie, X.},
 year = {2016},
 title = {Exciton Radiative Lifetime in Transition Metal Dichalcogenide Monolayers},
 pages = {205423},
 volume = {93},
 number = {20},
 issn = {0556-2805},
 journal = {Phys. Rev. B},
 doi = {10.1103/PhysRevB.93.205423}
}

@article{Mo.2020,
 abstract = {In this paper, we explore the impact of changing the growth conditions on the substrate surface during the metal-organic vapor phase epitaxy of 2D-transition metal dichalcogenides. We particularly study the growth of molybdenum disulfide (MoS2) on sapphire substrates at different temperatures. We show that a high temperature leads to a perfect epitaxial alignment of the MoS2 layer with respect to the sapphire substrate underneath, whereas a low temperature growth induces a 30° epitaxial alignment. This behavior is found to be related to the different sapphire top surface re-arrangement under H2S environment at different growth temperatures. Structural analyses conducted on the different samples confirm an improved layer quality at high temperatures. MoS2 channel-based metal-oxide-semiconductor field-effect transistors are fabricated showing improved device performance with channel layers grown at high temperature.},
 author = {Mo, Jiongjiong and {El Kazzi}, Salim and Mortelmans, Wouter and Mehta, Ankit Nalin and Sergeant, Stefanie and Smets, Quentin and Asselberghs, Inge and Huyghebaert, Cedric},
 year = {2020},
 title = {Importance of the Substrate's Surface Evolution During the MOVPE Growth of 2D-transition Metal Dichalcogenides},
 url = {https://iopscience.iop.org/article/10.1088/1361-6528/ab5ffd},
 pages = {125604},
 volume = {31},
 number = {12},
 issn = {0957-4484},
 journal = {Nanotechnology},
 doi = {10.1088/1361-6528/ab5ffd},
 file = {Mo, El Kazzi et al. 2020 - Importance of the substrate's surface:Attachments/Mo, El Kazzi et al. 2020 - Importance of the substrate's surface.pdf:application/pdf}
}

@article{Christopher.2017,
 abstract = {Monolayer molybdenum disulfide (MoS2) has emerged as a model system for studying many-body physics because the low dimensionality reduces screening leading to tightly bound states stable at room temperature. Further, the many-body states possess a pseudo-spin degree of freedom that corresponds with the two direct-gap valleys of the band structure, which can be optically manipulated. Here we focus on one bound state, the negatively charged trion. Unlike excitons, trions can radiatively decay with non-zero momentum by kicking out an electron, resulting in an asymmetric trion photoluminescence (PL) peak with a long low-energy tail and peak position that differs from the zero momentum trion energy. The asymmetry of the trion PL peak and resulting peak red-shift depends both on the trion size and a temperature-dependent contribution. Ignoring the trion asymmetry will result in over estimating the trion binding energy by nearly 20 meV at room temperature. We analyze the temperature-dependent PL to reveal the effective trion size, consistent with the literature, and the temperature dependence of the band gap and spin-orbit splitting of the valence band. This is the first time the temperature-dependence of the trion PL has been analyzed with such detail in any system.},
 author = {Christopher, Jason W. and Goldberg, Bennett B. and Swan, Anna K.},
 year = {2017},
 title = {Long Tailed Trions in Monolayer MoS$_2$: Temperature Dependent Asymmetry and Resulting Red-Shift of Trion Photoluminescence Spectra},
 url = {https://www.nature.com/articles/s41598-017-14378-w},
 pages = {14062},
 volume = {7},
 number = {1},
 issn = {2045-2322},
 journal = {Sci. Rep.},
 doi = {10.1038/s41598-017-14378-w},
 file = {Christopher, Goldberg et al. 2017 - Long tailed trions in monolayer:Attachments/Christopher, Goldberg et al. 2017 - Long tailed trions in monolayer.pdf:application/pdf}
}

@article{Schuler.2019,
 abstract = {Structural defects in 2D materials offer an effective way to engineer new material functionalities beyond conventional doping. We report on the direct experimental correlation of the atomic and electronic structure of a sulfur vacancy in monolayer WS{\_}{2} by a combination of CO-tip noncontact atomic force microscopy and scanning tunneling microscopy. Sulfur vacancies, which are absent in as-grown samples, were deliberately created by annealing in vacuum. Two energetically narrow unoccupied defect states followed by vibronic sidebands provide a unique fingerprint of this defect. Direct imaging of the defect orbitals, together with ab~initio GW calculations, reveal that the large splitting of 252$\pm$4  meV between these defect states is induced by spin-orbit coupling.},
 author = {Schuler, Bruno and Qiu, Diana Y. and Refaely-Abramson, Sivan and Kastl, Christoph and Chen, Christopher T. and Barja, Sara and Koch, Roland J. and Ogletree, D. Frank and Aloni, Shaul and Schwartzberg, Adam M. and Neaton, Jeffrey B. and Louie, Steven G. and Weber-Bargioni, Alexander},
 year = {2019},
 title = {Large Spin-Orbit Splitting of Deep In-Gap Defect States of Engineered Sulfur Vacancies in Monolayer WS$_2$},
 pages = {076801},
 volume = {123},
 number = {7},
 journal = {Phys. Rev. Lett.},
 doi = {10.1103/PhysRevLett.123.076801},
 file = {Schuler, Qiu et al. 2019 - Large Spin-Orbit Splitting of Deep:Attachments/Schuler, Qiu et al. 2019 - Large Spin-Orbit Splitting of Deep.pdf:application/pdf}
}

@article{amani_near-unity_2015,
	title = {Near-unity Photoluminescence Quantum Yield in {MoS$_2$}},
	volume = {350},
	url = {https://www.science.org/doi/10.1126/science.aad2114} ,
	doi = {10.1126/science.aad2114},
	abstract = {Two-dimensional (2D) transition metal dichalcogenides have emerged as a promising material system for optoelectronic applications, but their primary figure of merit, the room-temperature photoluminescence quantum yield ({QY}), is extremely low. The prototypical 2D material molybdenum disulfide ({MoS}2) is reported to have a maximum {QY} of 0.6\%, which indicates a considerable defect density. Here we report on an air-stable, solution-based chemical treatment by an organic superacid, which uniformly enhances the photoluminescence and minority carrier lifetime of {MoS}2 monolayers by more than two orders of magnitude. The treatment eliminates defect-mediated nonradiative recombination, thus resulting in a final {QY} of more than 95\%, with a longest-observed lifetime of 10.8 ± 0.6 nanoseconds. Our ability to obtain optoelectronic monolayers with near-perfect properties opens the door for the development of highly efficient light-emitting diodes, lasers, and solar cells based on 2D materials.},
	pages = {1065--1068},
	number = {6264},
	journal = {Science},
	author = {Amani, Matin and Lien, Der-Hsien and Kiriya, Daisuke and Xiao, Jun and Azcatl, Angelica and Noh, Jiyoung and Madhvapathy, Surabhi R. and Addou, Rafik and {KC}, Santosh and Dubey, Madan and Cho, Kyeongjae and Wallace, Robert M. and Lee, Si-Chen and He, Jr-Hau and Ager, Joel W. and Zhang, Xiang and Yablonovitch, Eli and Javey, Ali},
	urldate = {2025-06-20},
	year = {2015},
}


@article{kim_synthetic_2019,
	title = {Synthetic {WSe$_2$} Monolayers with High Photoluminescence Quantum Yield},
	volume = {5},
	url = {https://www.science.org/doi/10.1126/sciadv.aau4728}  ,
	doi = {10.1126/sciadv.aau4728},
	abstract = {In recent years, there have been tremendous advancements in the growth of monolayer transition metal dichalcogenides ({TMDCs}) by chemical vapor deposition ({CVD}). However, obtaining high photoluminescence quantum yield ({PL} {QY}), which is the key figure of merit for optoelectronics, is still challenging in the grown monolayers. Specifically, the as-grown monolayers often exhibit lower {PL} {QY} than their mechanically exfoliated counterparts. In this work, we demonstrate synthetic tungsten diselenide ({WSe}2) monolayers with {PL} {QY} exceeding that of exfoliated crystals by over an order of magnitude. {PL} {QY} of {\textasciitilde}60\% is obtained in monolayer films grown by {CVD}, which is the highest reported value to date for {WSe}2 prepared by any technique. The high optoelectronic quality is enabled by the combination of optimizing growth conditions via tuning the halide promoter ratio, and introducing a simple substrate decoupling method via solvent evaporation, which also mechanically relaxes the grown films. The achievement of scalable {WSe}2 with high {PL} {QY} could potentially enable the emergence of technologically relevant devices at the atomically thin limit.},
	pages = {eaau4728},
	number = {1},
	journal = {Sci. Adv.},
	author = {Kim, Hyungjin and Ahn, Geun Ho and Cho, Joy and Amani, Matin and Mastandrea, James P. and Groschner, Catherine K. and Lien, Der-Hsien and Zhao, Yingbo and Ager, Joel W. and Scott, Mary C. and Chrzan, Daryl C. and Javey, Ali},
	urldate = {2025-06-12},
	year = {2019},
}

@article{li_revealing_2021,
	title = {Revealing the Interrelation Between C- and A-exciton Dynamics in Monolayer WS$_2$ via Transient Absorption Spectroscopy},
	volume = {119},
	issn = {0003-6951},
	url = {https://doi.org/10.1063/5.0060587  }                     ,
	doi = {10.1063/5.0060587 },
	abstract = {Two-dimensional transition metal dichalcogenides (TMDs) are emerging as a promising complement for traditional semiconductor materials in ultrathin optoelectronic device fields. Developing a better understanding of high-energy C-exciton dynamics is essential for efficiently extracting hot carriers and building high-performance TMD-based light-harnessing devices; however, insight into the C-exciton dynamics remains scarce. To further understand the C-exciton dynamics, here, we have unraveled the interrelation between C-exciton and band edge A-exciton dynamics in monolayer WS2 by transient absorption spectroscopy. It is found that the band edge A-excitons could effectively generate high-energy C-excitons via the many-body process, and, in turn, the hot carriers relaxing from C-excitons to band edge states could compensate and slow the decay of the A-excitons. The comprehensive understanding of the interrelation between C-exciton and A-exciton dynamics in monolayer TMDs may trigger the potential applications for future TMD-based light-harvesting devices.},
	number = {5},
	urldate = {2025-03-03},
	journal = {Appl. Phys. Lett.},
	author = {Li, Yuanzheng and Wu, Xianxin and Liu, Weizhen and Xu, Haiyang and Liu, Xinfeng},
	month = aug,
	year = {2021},
	pages = {051106},
}
@article{Zhu.2015,
 abstract = {The optical properties of monolayer transition metal dichalcogenides (TMDC) feature prominent excitonic natures. Here we report an experimental approach to measuring the exciton binding energy of monolayer WS$_2$ with linear differential transmission spectroscopy and two-photon photoluminescence excitation spectroscopy (TP-PLE). TP-PLE measurements show the exciton binding energy of 0.71 $\pm$ 0.01 eV around K valley in the Brillouin zone.},
 author = {Zhu, Bairen and Chen, Xi and Cui, Xiaodong},
 year = {2015},
 title = {Exciton Binding Energy of Monolayer WS$_2$},
 url = {https://www.nature.com/articles/srep09218},
 pages = {9218},
 volume = {5},
 number = {1},
 issn = {2045-2322},
 journal = {Sci. Rep.},
 doi = {10.1038/srep09218  },
 file = {Zhu, Chen et al. 2015 - Exciton binding energy of monolayer:Attachments/Zhu, Chen et al. 2015 - Exciton binding energy of monolayer.pdf:application/pdf}
}
@article{Staiger.2015,
author = {M. Staiger and R. Gillen and N. Scheuschner and O. Ochedowski and F. Kampmann and M. Schleberger and C. Thomsen and J. Maultzsch},
 year = {2015},
 title = {Splitting of the Monolayer Out-of-Plane {A}'1 {R}aman Mode in Few-Layer WS$_2$},
 pages = {195419},
 volume = {91},
 journal = {Phys. Rev. B},
 doi = {10.1103/PhysRevB.91.235409 }
}
% This file was created with Citavi 6.14.0.0

@article{Berkdemir.2013,
 abstract = {The Raman scattering of single- and few-layered WS2 is studied as a function of the number of S-W-S layers and the excitation wavelength in the visible range (488, 514 and 647 nm). For the three excitation wavelengths used in this study, the frequency of the A1g(\textgreek{G}) phonon mode monotonically decreases with the number of layers. For single-layer WS2, the 514.5 nm laser excitation generates a second-order Raman resonance involving the longitudinal acoustic mode (LA(M)). This resonance results from a coupling between the electronic band structure and lattice vibrations. First-principles calculations were used to determine the electronic and phonon band structures of single-layer and bulk WS2. The reduced intensity of the 2LA mode was then computed, as a function of the laser wavelength, from the fourth-order Fermi golden rule. Our observations establish an unambiguous and nondestructive Raman fingerprint for identifying single- and few-layered WS2 films.},
 author = {Berkdemir, Ayse and Guti{\'e}rrez, Humberto R. and Botello-M{\'e}ndez, Andr{\'e}s R. and Perea-L{\'o}pez, N{\'e}stor and El{\'i}as, Ana Laura and Chia, Chen-Ing and Wang, Bei and Crespi, Vincent H. and L{\'o}pez-Ur{\'i}as, Florentino and Charlier, Jean-Christophe and Terrones, Humberto and Terrones, Mauricio},
 year = {2013},
 title = {Identification of Individual and Few Layers of WS$_2$ Using Raman Spectroscopy},
 url = {https://www.nature.com/articles/srep01755},
 keywords = {Computational nanotechnology;interfaces and thin films;Nanoparticles;Surfaces;Two-dimensional materials},
 pages = {1--8},
 volume = {3},
 number = {1},
 issn = {2045-2322},
 journal = {Sci. Rep.},
 doi = {10.1038/srep01755 },
 file = {Identification of individual and few layers of WS2 using:Attachments/Identification of individual and few layers of WS2 using.pdf:application/pdf}
}


@article{Zhao.2013,
 abstract = {Thickness is one of the fundamental parameters that define the electronic, optical, and thermal properties of two-dimensional (2D) crystals. Phonons in molybdenum disulfide (MoS2) were recently found to exhibit unique thickness dependence due to the interplay between short and long range interactions. Here we report Raman spectra of atomically thin sheets of WS2 and WSe2, isoelectronic compounds of MoS2, in the mono- to few-layer thickness regime. We show that, similar to the case of MoS2, the characteristic A1g and E2g(1) modes exhibit stiffening and softening with increasing number of layers, respectively, with a small shift of less than 3 cm(-1) due to large mass of the atoms. Thickness dependence is also observed in a series of multiphonon bands arising from overtone, combination, and zone edge phonons, whose intensity exhibit significant enhancement in excitonic resonance conditions. Some of these multiphonon peaks are found to be absent only in monolayers. These features provide a unique fingerprint and rapid identification for monolayer flakes.},
 author = {Zhao, Weijie and Ghorannevis, Zohreh and Amara, Kiran Kumar and Pang, Jing Ren and Toh, Minglin and Zhang, Xin and Kloc, Christian and Tan, Ping Heng and Eda, Goki},
 year = {2013},
 title = {Lattice Dynamics in Mono- and Few-Layer Sheets of WS$_2$ and WSe$_2$},
 url = {https://pubs.rsc.org/en/content/articlelanding/2013/nr/c3nr03052k},
 pages = {9677--9683},
 volume = {5},
 number = {20},
 issn = {2040-3372},
 journal = {Nanoscale},
 doi = {10.1039/C3NR03052K },
 file = {Zhao, Ghorannevis et al. 2013 - Lattice dynamics in mono:Attachments/Zhao, Ghorannevis et al. 2013 - Lattice dynamics in mono.pdf:application/pdf}
}



% This file was created with Citavi 6.14.0.0

@article{Bertolazzi.2017,
 abstract = {Irradiation of 2D sheets of transition metal dichalcogenides with ion beams has emerged as an effective approach to engineer chemically active defects in 2D materials. In this context, argon-ion bombardment has been utilized to introduce sulfur vacancies in monolayer molybdenum disulfide (MoS2 ). However, a detailed understanding of the effects of generated defects on the functional properties of 2D MoS2 is still lacking. In this work, the correlation between critical electronic device parameters and the density of sulfur vacancies is systematically investigated through the fabrication and characterization of back-gated monolayer MoS2 field-effect transistors (FETs) exposed to a variable fluence of low-energy argon ions. The electrical properties of pristine and ion-irradiated FETs can be largely improved/recovered by exposing the devices to vapors of short linear thiolated molecules. Such a solvent-free chemical treatment-carried out strictly under inert atmosphere-rules out secondary healing effects induced by oxygen or oxygen-containing molecules. The results provide a guideline to design monolayer MoS2 optoelectronic devices with a controlled density of sulfur vacancies, which can be further exploited to introduce ad hoc molecular functionalities by means of thiol chemistry approaches.},
 author = {Bertolazzi, Simone and Bonacchi, Sara and Nan, Guangjun and Pershin, Anton and Beljonne, David and Samor{\`i}, Paolo},
 year = {2017},
 title = {Engineering Chemically Active Defects in Monolayer MoS$_2$ Transistors via Ion-Beam Irradiation and Their Healing via Vapor Deposition of Alkanethiols},
 url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201606760}                ,
 pages = {1606760},
 volume = {29},
 number = {18},
 issn = {1521-4095},
 journal = {Adv. Mater.},
 doi = {10.1002/adma.201606760},
 file = {Bertolazzi, Bonacchi et al. 2017 - Engineering Chemically Active Defects:Attachments/Bertolazzi, Bonacchi et al. 2017 - Engineering Chemically Active Defects.pdf:application/pdf}
}


@article{Liu.2020,
 abstract = {As defects usually limit the exciton diffusion in 2D transition metal dichalcogenides (TMDCs), the interaction knowledge of defects and exciton transport is crucial for achieving efficient TMDC-based devices. A direct visualization of defect-modulated exciton transport is developed in few-layer WS2 by ultrafast transient absorption microscopy. Atomic-scale defects are introduced by argon plasma treatment and identified by aberration-corrected scanning transmission electron microscopy. Neutral excitons can be captured by defects to form bound excitons in 7.75-17.88 ps, which provide a nonradiative relaxation channel, leading to decreased exciton lifetime and diffusion coefficient. The exciton diffusion length of defective sample has a drastic reduction from 349.44 to 107.40 nm. These spatially and temporally resolved measurements reveal the interaction mechanism between defects and exciton transport dynamics in 2D TMDCs, giving a guideline for designing high-performance TMDC-based devices.},
 author = {Liu, Huan and Wang, Chong and Zuo, Zhengguang and Liu, Dameng and Luo, Jianbin},
 year = {2020},
 title = {Direct Visualization of Exciton Transport in Defective Few-Layer WS$_2$ by Ultrafast Microscopy},
 pages = {e1906540},
 volume = {32},
 number = {2},
 issn = {1521-4095},
 journal = {Adv. Mater.},
 doi = {10.1002/adma.201906540}
}


@article{Lu.2020,
 abstract = {Various approaches have been developed to produce MoS2 monolayers and multilayers. Using plasma and thermal thinning, layer-by-layer thinning processes were developed to produce MoS2 monolayer and multilayers. However, an atomic-level understanding of the thinning mechanism and defects created in these processes is not clear. In this paper, we studied the impact on surface structures of bulk MoS2 by argon ion (Ar+) bombardments and thermal annealing using an ultra-high vacuum (UHV) scanning tunneling microscope (STM). The STM images obtained before and after Ar+ bombardments show that low-energy (50~eV) Ar+ ions can remove single atoms from the surface and fragment the top sulfur layer resulting in single sulfur vacancy point defects and atomic pits on the MoS2 surface. Higher energy (100~eV) Ar+ ions can penetrate deeper and remove the topmost MoS2 trilayer. After bombardment with an Ar+ beam of 500~eV, the MoS2 surface appeared as granulated nanostructures consisting of 1--3~nm nanoparticles. Upon thermal annealing, topmost sulfur atoms were removed through sublimation after heating at 650~°C for 5~min and deeper atom sublimation was observed with longer annealing time, resulting in granulated nanostructures on the MoS2 surface.},
 author = {Lu, Weigang and Birmingham, Blake and Zhang, Zhenrong},
 year = {2020},
 title = {Defect Engineering on MoS$_2$ Surface with Argon Ion Bombardments and Thermal Annealing},
 url = {https://www.sciencedirect.com/science/article/pii/S0169433220322182},
 pages = {147461},
 volume = {532},
 issn = {0169-4332},
 journal = {Appl. Surf. Sci.},
 doi = {10.1016/j.apsusc.2020.147461}
}

%start diffusion paper
@article{chubarov_wafer-scale_2021,
	title = {Wafer-{Scale} {Epitaxial} {Growth} of {Unidirectional} {WS$_2$} {Monolayers} on {Sapphire}},
	volume = {15},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.0c06750}                ,
	doi = {10.1021/acsnano.0c06750},
	abstract = {Realization of wafer-scale single-crystal films of transition metal dichalcogenides (TMDs) such as WS2 requires epitaxial growth and coalescence of oriented domains to form a continuous monolayer. The domains must be oriented in the same crystallographic direction on the substrate to inhibit the formation of inversion domain boundaries (IDBs), which are a common feature of layered chalcogenides. Here we demonstrate fully coalesced unidirectional WS2 monolayers on 2 in. diameter c-plane sapphire by metalorganic chemical vapor deposition using a multistep growth process to achieve epitaxial WS2 monolayers with low in-plane rotational twist (0.09°). Transmission electron microscopy analysis reveals that the WS2 monolayers are largely free of IDBs but instead have translational boundaries that arise when WS2 domains with slightly offset lattices merge together. By regulating the monolayer growth rate, the density of translational boundaries and bilayer coverage were significantly reduced. The unidirectional orientation of domains is attributed to the presence of steps on the sapphire surface coupled with growth conditions that promote surface diffusion, lateral domain growth, and coalescence while preserving the aligned domain structure. The transferred WS2 monolayers show neutral and charged exciton emission at 80 K with negligible defect-related luminescence. Back-gated WS2 field effect transistors exhibited an ION/OFF of ∼107 and mobility of 16 cm2/(V s). The results demonstrate the potential of achieving wafer-scale TMD monolayers free of inversion domains with properties approaching those of exfoliated flakes.},
	number = {2},
	urldate = {2025-04-03},
	journal = {ACS Nano},
	author = {Chubarov, Mikhail and Choudhury, Tanushree H. and Hickey, Danielle Reifsnyder and Bachu, Saiphaneendra and Zhang, Tianyi and Sebastian, Amritanand and Bansal, Anushka and Zhu, Haoyue and Trainor, Nicholas and Das, Saptarshi and Terrones, Mauricio and Alem, Nasim and Redwing, Joan M.},
	month = feb,
	year = {2021},
	pages = {2532--2541},
}
@article{Bianchi.2024,
 abstract = {Two-dimensional (2D) materials as tungsten disulphide (WS2 ) are rising as the ideal platform for the next generation of nanoscale devices due to the excellent electric-transport and optical properties. However, the presence of defects in the as grown samples represents one of the main limiting factors for commercial applications. At the same time, WS2 properties are frequently tailored by introducing impurities at specific sites. Aim of this review paper is to present a complete description and discussion of the effects of both intentional and unintentional defects in WS2 , by an in depth analysis of the recent experimental and theoretical investigations reported in the literature. First, the most frequent intrinsic defects in WS2 are presented and their effects in the readily synthetized material are discussed. Possible solutions to remove and heal unintentional defects are also analyzed. Following, different doping schemes are reported, including the traditional substitution approach and innovative techniques based on the surface charge transfer with adsorbed atoms or molecules. The plethora of WS2 monolayer modifications presented in this review and the systematic analysis of the corresponding optical and electronic properties, represent strategic degrees of freedom the researchers may exploit to tailor WS2 optical and electronic properties for specific device~applications.},
 author = {Bianchi, Michele Giovanni and Risplendi, Francesca and {Re Fiorentin}, Michele and Cicero, Giancarlo},
 year = {2024},
 title = {Engineering the Electrical and Optical Properties of WS$_2$ Monolayers via Defect Control},
 url = {https://onlinelibrary.wiley.com/doi/full/10.1002/advs.202305162}                   ,
 pages = {e2305162},
 volume = {11},
 number = {4},
 issn = {2198-3844},
 journal = {Adv. Sci.},
 doi = {10.1002/advs.202305162},
 file = {Bianchi, Risplendi et al. 2024 - Engineering the Electrical and Optical:Attachments/Bianchi, Risplendi et al. 2024 - Engineering the Electrical and Optical.pdf:application/pdf}
}
@article{wan_low-defect-density_2022,
	title = {Low-Defect-Density {WS$_2$} by Hydroxide Vapor Phase Deposition},
	volume = {13},
	copyright = {2022 The Author(s)},
	issn = {2041-1723},
	url = {https://www.nature.com/articles/s41467-022-31886-0},
	doi = {10.1038/s41467-022-31886-0},
	abstract = {Two-dimensional (2D) semiconducting monolayers such as transition metal dichalcogenides (TMDs) are promising channel materials to extend Moore’s Law in advanced electronics. Synthetic TMD layers from chemical vapor deposition (CVD) are scalable for fabrication but notorious for their high defect densities. Therefore, innovative endeavors on growth reaction to enhance their quality are urgently needed. Here, we report that the hydroxide W species, an extremely pure vapor phase metal precursor form, is very efficient for sulfurization, leading to about one order of magnitude lower defect density compared to those from conventional CVD methods. The field-effect transistor (FET) devices based on the proposed growth reach a peak electron mobility {\textasciitilde}200 cm2/Vs ({\textasciitilde}800 cm2/Vs) at room temperature (15 K), comparable to those from exfoliated flakes. The FET device with a channel length of 100 nm displays a high on-state current of {\textasciitilde}400 µA/µm, encouraging the industrialization of 2D materials.},
	language = {en},
	number = {1},
	urldate = {2025-04-03},
	journal = {Nat. Commun.},
	author = {Wan, Yi and Li, En and Yu, Zhihao and Huang, Jing-Kai and Li, Ming-Yang and Chou, Ang-Sheng and Lee, Yi-Te and Lee, Chien-Ju and Hsu, Hung-Chang and Zhan, Qin and Aljarb, Areej and Fu, Jui-Han and Chiu, Shao-Pin and Wang, Xinran and Lin, Juhn-Jong and Chiu, Ya-Ping and Chang, Wen-Hao and Wang, Han and Shi, Yumeng and Lin, Nian and Cheng, Yingchun and Tung, Vincent and Li, Lain-Jong},
	month = jul,
	year = {2022},
	keywords = {Synthesis and processing, Two-dimensional materials},
	pages = {4149},
}

@article{Deng.2020,
 abstract = {Two-dimensional hybrid organic-inorganic perovskites with strongly bound excitons and tunable structures are desirable for optoelectronic applications. Exciton transport and annihilation are two key processes in determining device efficiencies; however, a thorough understanding of these processes is hindered by that annihilation rates are often convoluted with exciton diffusion constants. Here we employ transient absorption microscopy to disentangle quantum-well-thickness-dependent exciton diffusion and annihilation in two-dimensional perovskites, unraveling the key role of electron-hole interactions and dielectric screening. The exciton diffusion constant is found to increase with quantum-well thickness, ranging from 0.06 $\pm$ 0.03 to 0.34 $\pm$ 0.03 cm2 s-1, which leads to long-range exciton diffusion over hundreds of nanometers. The exciton annihilation rates are more than one order of magnitude lower than those found in the monolayers of transition metal dichalcogenides. The combination of long-range exciton transport and slow annihilation highlights the unique attributes of two-dimensional perovskites as an exciting class of optoelectronic materials.},
 author = {Deng, Shibin and Shi, Enzheng and Yuan, Long and Jin, Linrui and Dou, Letian and Huang, Libai},
 year = {2020},
 title = {Long-range Exciton Transport and Slow Annihilation in Two-dimensional Hybrid Perovskites},
 url = {https://www.nature.com/articles/s41467-020-14403-z},
 pages = {664},
 volume = {11},
 number = {1},
 issn = {2041-1723},
 journal = {Nat. Commun.},
 doi = {10.1038/s41467-020-14403-z},
 file = {Deng, Shi et al. 2020 - Long-range exciton transport and slow:Attachments/Deng, Shi et al. 2020 - Long-range exciton transport and slow.pdf:application/pdf}
}


@article{Goodman.2020,
 author = {Goodman, A. J. and Lien, D.-H. and Ahn, G. H. and Spiegel, L. L. and Amani, M. and Willard, A. P. and Javey, A. and Tisdale, W. A.},
 year = {2020},
 title = {Substrate-Dependent Exciton Diffusion and Annihilation in Chemically Treated MoS$_2$ and WS$_2$},
 pages = {12175--12184},
 volume = {124},
 number = {22},
 issn = {1932-7447},
 journal = {J. Phys. Chem. C},
 doi = {10.1021/acs.jpcc.0c04000},
 file = {Goodman, Lien et al. 2020 - Substrate-Dependent Exciton Diffusion and Annihilation:Attachments/Goodman, Lien et al. 2020 - Substrate-Dependent Exciton Diffusion and Annihilation.pdf:application/pdf}
}


@article{Kulig.2018,
 abstract = {We directly monitor exciton propagation in freestanding and SiO{\_}{2}-supported WS{\_}{2} monolayers through spatially and time-resolved microphotoluminescence under ambient conditions. We find a highly nonlinear behavior with characteristic, qualitative changes in the spatial profiles of the exciton emission and an effective diffusion coefficient increasing from 0.3 to more than 30  cm{\^{}}{2}/s, depending on the injected exciton density. Solving the diffusion equation while accounting for Auger recombination allows us to identify and quantitatively understand the main origin of the increase in the observed diffusion coefficient. At elevated excitation densities, the initial Gaussian distribution of the excitons evolves into long-lived halo shapes with \textgreek{m}m-scale diameter, indicating additional memory effects in the exciton dynamics.},
 author = {Kulig, Marvin and Zipfel, Jonas and Nagler, Philipp and Blanter, Sofia and Sch{\"u}ller, Christian and Korn, Tobias and Paradiso, Nicola and Glazov, Mikhail M. and Chernikov, Alexey},
 year = {2018},
 title = {Exciton Diffusion and Halo Effects in Monolayer Semiconductors},
 pages = {207401},
 volume = {120},
 number = {20},
 journal = {Phys. Rev. Lett.},
 doi = {10.1103/PhysRevLett.120.207401},
 file = {Kulig, Zipfel et al. 2018 - Exciton Diffusion and Halo Effects:Attachments/Kulig, Zipfel et al. 2018 - Exciton Diffusion and Halo Effects.pdf:application/pdf}
}


@article{Kumar.2023,
 abstract = {Exciton-exciton annihilation (EEA), an important loss channel in optoelectronic devices and photosynthetic complexes, has conventionally been assumed to be an incoherent, diffusion-limited process. Here we challenge this assumption by experimentally demonstrating the ability to control EEA in molecular aggregates using the quantum phase relationships of excitons. We employed time-resolved photoluminescence microscopy to independently determine exciton diffusion constants and annihilation rates in two substituted perylene diimide aggregates featuring contrasting excitonic phase envelopes. Low-temperature EEA rates were found to differ by more than two orders of magnitude for the two compounds, despite comparable diffusion constants. Simulated rates based on a microscopic theory, in excellent agreement with experiments, rationalize this EEA behaviour based on quantum interference arising from the presence or absence of spatial phase oscillations of delocalized excitons. These results offer an approach for designing molecular materials using quantum interference where low annihilation can coexist with high exciton concentrations and mobilities.},
 author = {Kumar, Sarath and Dunn, Ian S. and Deng, Shibin and Zhu, Tong and Zhao, Qiuchen and Williams, Olivia F. and Tempelaar, Roel and Huang, Libai},
 year = {2023},
 title = {Exciton Annihilation in Molecular Aggregates Suppressed through Quantum Interference},
 url = {https://www.nature.com/articles/s41557-023-01233-x},
 pages = {1118--1126},
 volume = {15},
 number = {8},
 issn = {1755-4349},
 journal = {Nat. Chem.},
 doi = {10.1038/s41557-023-01233-x},
 file = {Kumar, Dunn et al. 2023 - Exciton annihilation in molecular aggregates:Attachments/Kumar, Dunn et al. 2023 - Exciton annihilation in molecular aggregates.pdf:application/pdf}
}

@article{Smoluchowski.1918,
 author = {Smoluchowski, M. v.},
 year = {1918},
 title = {Versuch Einer Mathematischen Theorie Der Koagulationskinetik Kolloider L{\"o}sungen},
 pages = {129--168},
 volume = {92U},
 number = {1},
 issn = {0942-9352},
 journal = {Z. Phys. Chem.},
 doi = {10.1515/zpch-1918-9209}
}


@article{Sortino.2023,
 abstract = {Two-dimensional (2D) semiconductors possess strongly bound excitons, opening novel opportunities for engineering light-matter interaction at the nanoscale. However, their in-plane confinement leads to large non-radiative exciton-exciton annihilation (EEA) processes, setting a fundamental limit for their photonic applications. In this work, we demonstrate suppression of EEA via enhancement of light-matter interaction in hybrid 2D semiconductor-dielectric nanophotonic platforms, by coupling excitons in WS2 monolayers with optical Mie resonances in dielectric nanoantennas. The hybrid system reaches an intermediate light-matter coupling regime, with photoluminescence enhancement factors up to 102. Probing the exciton ultrafast dynamics reveal suppressed EEA for coupled excitons, even under high exciton densities {\textgreater}1012 cm-2. We extract EEA coefficients in the order of 10-3, compared to 10-2 for uncoupled monolayers, as well as a Purcell factor of 4.5. Our results highlight engineering the photonic environment as a route to achieve higher quantum efficiencies, for low-power hybrid devices, and larger exciton densities, towards strongly correlated excitonic phases in 2D semiconductors.},
 author = {Sortino, Luca and G{\"u}lm{\"u}s, Merve and Tilmann, Benjamin and de {S Menezes}, Leonardo and Maier, Stefan A.},
 year = {2023},
 title = {Radiative Suppression of Exciton-Exciton Annihilation in a Two-Dimensional Semiconductor},
 url = {https://www.nature.com/articles/s41377-023-01249-5},
 pages = {202},
 volume = {12},
 number = {1},
 issn = {2047-7538},
 journal = {Light Sci. Appl.},
 doi = {10.1038/s41377-023-01249-5},
 file = {Sortino, G{\"u}lm{\"u}s et al. 2023 - Radiative suppression of exciton-exciton annihilation:Attachments/Sortino, G{\"u}lm{\"u}s et al. 2023 - Radiative suppression of exciton-exciton annihilation.pdf:application/pdf}
}


@article{Suna.1970,
 author = {Suna, A.},
 year = {1970},
 title = {Kinematics of Exciton-Exciton Annihilation in Molecular Crystals},
 pages = {1716--1739},
 volume = {1},
 number = {4},
 issn = {0556-2805},
 journal = {Phys. Rev. B},
 doi = {10.1103/PhysRevB.1.1716}
}


@article{Uddin.2022,
 abstract = {Dominant recombination pathways in monolayer transition metal dichalcogenides (TMDCs) depend primarily on background carrier concentration, generation rate, and applied strain. Charged excitons formed in the presence of background carriers mainly recombine nonradiatively. Neutral excitons recombine completely radiatively at low generation rates, but experience nonradiative exciton-exciton annihilation (EEA) at high generation rates. Strain can suppress EEA, resulting in near-unity photoluminescence quantum yield (PL QY) at all exciton densities. Although exciton diffusion is the primary channel of energy transport in excitonic materials and a critical optoelectronic design consideration, the combined effects of these factors on exciton diffusion are not clearly understood. In this work, we decouple the diffusion of neutral and charged excitons with chemical counterdoping and explore the effect of strain and generation rate on exciton diffusion. According to the standard semiconductor paradigm, a shorter carrier recombination lifetime should lead to a smaller diffusion length. Surprisingly, we find that increasing generation rate shortens the exciton lifetime but increases the diffusion length in unstrained monolayers of TMDCs. When we suppress EEA by strain, both lifetime and diffusion length become independent of generation rate. During EEA one exciton nonradiatively recombines and kinetically energizes another exciton, which then diffuses fast. Our results probe concentration-dependent diffusion of pure neutral excitons by counterdoping and elucidate how strain controls exciton transport and many-body interactions in TMDC monolayers.},
 author = {Uddin, Shiekh Zia and Higashitarumizu, Naoki and Kim, Hyungjin and Yi, Jun and Zhang, Xiang and Chrzan, Daryl and Javey, Ali},
 year = {2022},
 title = {Enhanced Neutral Exciton Diffusion in Monolayer WS$_2$ by Exciton-Exciton Annihilation},
 pages = {8005--8011},
 volume = {16},
 number = {5},
 journal = {ACS Nano},
 doi = {10.1021/acsnano.2c00956}
}
%end diffusion papers



% This file was created with Citavi 6.14.0.0

@article{Wang.2021,
 author = {Wang, Yu-Han and Ho, Hsin-Mei and Ho, Xuan-Long and Lu, Li-Syuan and Hsieh, Shang-Hsien and Huang, Shuei-De and Chiu, Hsiang-Chih and Chen, Chia-Hao and Chang, Wen-Hao and White, Jonathon David and Tang, Yu-Hui and Woon, Wei-Yen},
 year = {2021},
 title = {Photoluminescence Enhancement in WS$_2$ Nanosheets Passivated with Oxygen Ions: Implications for Selective Area Doping},
 pages = {11693--11699},
 volume = {4},
 number = {11},
 issn = {2574-0970},
 journal = {ACS Appl. Nano Mater.},
 doi = {10.1021/acsanm.1c02265 }
}


@article{zhang_defect-enhanced_2021,
	title = {Defect-{Enhanced} {Exciton}–{Exciton} {Annihilation} in {Monolayer} {Transition} {Metal} {Dichalcogenides} at {High} {Exciton} {Densities}},
	volume = {8},
	url = {https://doi.org/10.1021/acsphotonics.1c00932          }     ,
	doi = {10.1021/acsphotonics.1c00932 },
	abstract = {The exciton–exciton annihilation (EEA) process easily occurs in monolayer transition metal dichalcogenides (TMDs) because of the strong Coulomb interaction and quantum confinement effect, which enhance the many-body interaction of excitons. This process can affect the performance of the optoelectronic devices. It is crucial to examine the effect of defect states on the EEA process and determine whether it is comparable to that at the low excitation intensities, particularly when applied to laser devices at a high exciton density. In this study, femtosecond transient absorption spectroscopy was used to explore the EEA process of four types of CVD-grown monolayer TMDs (i.e., WS2, WSe2, MoS2, and MoSe2). We demonstrated that the defect-assisted EEA process of local excitons is enhanced and plays a key role in the exciton relaxation process at high exciton densities of approximately 1012 cm–2 below a Mott density of approximately 1013 cm–2. The measured EEA rates for WS2, WSe2, MoSe2, and MoS2 were 0.016, 0.026, 0.049, and 0.102 cm2/s, respectively, implying that EEA is enhanced as defect states increase in monolayer TMDs. Our results provide a profound insight into the effect of defect states on the EEA process in monolayer TMDs at high exciton densities.},
	number = {9},
	urldate = {2025-02-05},
	journal = {ACS Photonics},
	author = {Zhang, Tianju and Wang, Jun},
	month = sep,
	year = {2021},
	pages = {2770--2780},
}

@article{yu_fundamental_2016,
	title = {Fundamental Limits of Exciton-Exciton Annihilation for Light Emission in Transition Metal Dichalcogenide Monolayers},
	volume = {93},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.93.201111},
	doi = {10.1103/PhysRevB.93.201111},
	abstract = {We quantitatively illustrate the fundamental limit that exciton-exciton annihilation (EEA) may impose on the light emission of monolayer transition metal dichalcogenide (TMDC) materials. The EEA in TMDC monolayers shows a dependence on the interaction with substrates as its rate increases from 0.1c⁢m2/s (0.05c⁢m2/s) to 0.3c⁢m2/s (0.1c⁢m2/s) with the substrates removed for W⁢S2 (Mo⁢S2) monolayers. It turns to be the major pathway of exciton decay and dominates the luminescence efficiency when the exciton density is beyond 1010c⁢m−2 in suspended monolayers or 1011c⁢m−2 in supported monolayers. This sets an upper limit on the density of injected charges in light-emission devices for the realization of optimal luminescence efficiency. The strong EEA rate also dictates the pumping threshold for population inversion in the monolayers to be 12–18⁢MW/c⁢m2 (optically) or 2.5–4×105⁢A/c⁢m2 (electrically).},
	number = {20},
	urldate = {2025-02-05},
	journal = {Phys. Rev. B},
	author = {Yu, Yiling and Yu, Yifei and Xu, Chao and Barrette, Andy and Gundogdu, Kenan and Cao, Linyou},
	month = may,
	year = {2016},
	pages = {201111},
}

@article{MaYing.2005,
author = {Ma, Ying-Zhong and Valkunas, Leonas and Dexheimer, Susan L. and Bachilo, Sergei M. and Fleming, Graham R.},
address = {COLLEGE PK},
copyright = {Copyright 2009 Elsevier B.V., All rights reserved.},
issn = {0031-9007},
journal = {Phys. Rev. Lett.},
keywords = {Nanotubes ; Physical sciences ; Physics},
language = {eng},
number = {15},
pages = {157402.1-157402.4},
publisher = {Amer Physical Soc},
title = {Femtosecond Spectroscopy of Optical Excitations in Single-Walled Carbon Nanotubes: Evidence for Exciton-Exciton Annihilation},
doi = {10.1103/PhysRevLett.94.157402},
volume = {94},
year = {2005},
abstract = {Frequency-resolved femtosecond transient absorption spectra and kinetics measured by optical excitation of the second and first electronic transitions of the (8,3) single-walled carbon nanotube species reveal a unique mutual response between these transitions. Based on the analysis of the spectra, kinetics, and their distinct amplitude dependence on the pump intensity observed at these transitions, we conclude that these observations originate from both the excitonic origin of the spectrum and nonlinear exciton annihilation.},
}

@article{liu_neutral_2019,
	title = {Neutral and Defect-induced Exciton Annihilation in Defective Monolayer {WS$_2$}},
	volume = {11},
	url = {https://pubs.rsc.org/en/content/articlelanding/2019/nr/c9nr00967a},
	doi = {10.1039/C9NR00967A},
	language = {en},
	number = {16},
	urldate = {2025-03-03},
	journal = {Nanoscale},
	author = {Liu, Huan and Wang, Chong and Liu, Dameng and Luo, Jianbin},
	year = {2019},
	pages = {7913--7920},
}

@article{li_defect-mediated_2019,
	title = {Defect-{Mediated} {Charge}-{Carrier} {Trapping} and {Nonradiative} {Recombination} in {WSe$_2$} {Monolayers}},
	volume = {141},
	issn = {0002-7863},
	url = {https://doi.org/10.1021/jacs.9b04663}       ,
	doi = {10.1021/jacs.9b04663},
	abstract = {Nonradiative charge-carrier recombination in transition-metal dichalcogenide (TMD) monolayers severely limits their use in solar energy conversion technologies. Because defects serve as recombination sites, developing a quantitative description of charge-carrier dynamics in defective TMD monolayers can shed light on recombination mechanisms. Herein we report a first-principles investigation of charge-carrier dynamics in pristine and defective WSe2 monolayers with three of the most probable defects, namely, Se vacancies, W vacancies, and SeW antisites. We predict that Se vacancies slow down recombination by nearly an order of magnitude relative to defect-free samples by breaking the monolayer’s symmetry and thereby reducing the spectral intensity of the A1g phonon mode that promotes recombination in the pristine monolayer. By contrast, we find W vacancies accelerate recombination by more than an order of magnitude, with half of the recombination events bypassing charge traps. The subsequent dynamics feature both charge trapping and charge-trap-assisted recombination. Although SeW antisites also slightly accelerate recombination, the predicted mechanism is different from the W vacancy case. First, a shallow energy level traps a photoexcited electron. Then, both shallow- and deep-trap-assisted recombination can occur simultaneously. Accelerated recombination arises for W vacancies and SeW antisites because they introduce new phonon modes that strongly couple to electron and hole dynamics. This work thus provides a detailed understanding of the mechanisms behind charge-carrier recombination in WSe2 monolayers with distinct defects. Thus, materials engineering, particularly to avoid W vacancies, could advance this technology. The insights derived are important for future design of high-performance photoactive devices based on WSe2 monolayers.},
	number = {26},
	urldate = {2025-03-03},
	journal = {J. Am. Chem. Soc.},
	author = {Li, Lesheng and Carter, Emily A.},
	month = jul,
	year = {2019},
	pages = {10451--10461},
}

@article{yuan_exciton_2015,
	title = {Exciton Dynamics and Annihilation in {WS$_2$} {2D} semiconductors},
	volume = {7},
	issn = {2040-3372},
	url = {https://pubs.rsc.org/en/content/articlelanding/2015/nr/c5nr00383k},
	doi = {10.1039/C5NR00383K},
	abstract = {We systematically investigate the exciton dynamics in monolayered, bilayered, and trilayered WS2 two-dimensional (2D) crystals by time-resolved photoluminescence (TRPL) spectroscopy. The exciton lifetime when free of exciton annihilation was determined to be 806 ± 37 ps, 401 ± 25 ps, and 332 ± 19 ps for WS2 monolayer, bilayer, and trilayer, respectively. By measuring the fluorescence quantum yields, we also establish the radiative and nonradiative lifetimes of the direct and indirect excitons. The exciton decay in monolayered WS2 exhibits a strong excitation density-dependence, which can be described using an exciton–exciton annihilation (two-particle Auger recombination) model. The exciton–exciton annihilation rate for monolayered, bilayered, and trilayered WS2 was determined to be 0.41 ± 0.02, (6.00 ± 1.09) × 10−3 and (1.88 ± 0.47) × 10−3 cm2 s−1, respectively. Notably, the exciton–exciton annihilation rate is two orders of magnitude faster in the monolayer than in the bilayer and trilayer. We attribute the much slower exciton–exciton annihilation rate in the bilayer and trilayer to reduced many-body interaction and phonon-assisted exciton–exciton annihilation of indirect excitons.},
	language = {en},
	number = {16},
	urldate = {2025-03-03},
	journal = {Nanoscale},
	author = {Yuan, Long and Huang, Libai},
	month = apr,
	year = {2015},
	pages = {7402--7408},
}

@article{cohen_growth-etch_2021,
	title = {Growth-{Etch} {Metal}–{Organic} {Chemical} {Vapor} {Deposition} {Approach} of {WS$_2$} {Atomic} {Layers}},
	volume = {15},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.0c05394} ,
	doi = {10.1021/acsnano.0c05394},
	abstract = {Metal–organic chemical vapor deposition (MOCVD) is one of the main methodologies used for thin-film fabrication in the semiconductor industry today and is considered one of the most promising routes to achieve large-scale and high-quality 2D transition metal dichalcogenides (TMDCs). However, if special measures are not taken, MOCVD suffers from some serious drawbacks, such as small domain size and carbon contamination, resulting in poor optical and crystal quality, which may inhibit its implementation for the large-scale fabrication of atomic-thin semiconductors. Here we present a growth-etch MOCVD (GE-MOCVD) methodology, in which a small amount of water vapor is introduced during the growth, while the precursors are delivered in pulses. The evolution of the growth as a function of the amount of water vapor, the number and type of cycles, and the gas composition is described. We show a significant domain size increase is achieved relative to our conventional process. The improved crystal quality of WS2 (and WSe2) domains wasis demonstrated by means of Raman spectroscopy, photoluminescence (PL) spectroscopy, and HRTEM studies. Moreover, time-resolved PL studies show very long exciton lifetimes, comparable to those observed in mechanically exfoliated flakes. Thus, the GE-MOCVD approach presented here may facilitate their integration into a wide range of applications.},
	number = {1},
	urldate = {2025-03-03},
	journal = {ACS Nano},
	author = {Cohen, Assael and Patsha, Avinash and Mohapatra, Pranab K. and Kazes, Miri and Ranganathan, Kamalakannan and Houben, Lothar and Oron, Dan and Ismach, Ariel},
	month = jan,
	year = {2021},
	pages = {526--538},
}


% This file was created with Citavi 6.14.0.0

@article{Shi.2013,
 abstract = {Femtosecond transient absorption spectroscopy and microscopy were employed to study exciton dynamics in suspended and Si$_3$N$_4$ substrate-supported monolayer and few-layer MoS$_2$ 2D crystals. Exciton dynamics for the monolayer and few-layer structures were found to be remarkably different from those of thick crystals when probed at energies near that of the lowest energy direct exciton (A exciton). The intraband relaxation rate was enhanced by more than 40 fold in the monolayer in comparison to that observed in the thick crystals, which we attributed to defect assisted scattering. Faster electron-hole recombination was found in monolayer and few-layer structures due to quantum confinement effects that lead to an indirect-direct band gap crossover. Nonradiative rather than radiative relaxation pathways dominate the dynamics in the monolayer and few-layer MoS$_2$. Fast trapping of excitons by surface trap states was observed in monolayer and few-layer structures, pointing to the importance of controlling surface properties in atomically thin crystals such as MoS$_2$ along with controlling their dimensions.},
 author = {Shi, Hongyan and Yan, Rusen and Bertolazzi, Simone and Brivio, Jacopo and Gao, Bo and Kis, Andras and Jena, Debdeep and Xing, Huili Grace and Huang, Libai},
 year = {2013},
 title = {Exciton Dynamics in Suspended Monolayer and Few-Layer MoS$_2$ 2D Crystals},
 pages = {1072--1080},
 volume = {7},
 number = {2},
 journal = {ACS Nano},
 doi = {10.1021/nn303973r},
 file = {Shi, Yan et al. 2013 - Exciton dynamics in suspended monolayer:Attachments/Shi, Yan et al. 2013 - Exciton dynamics in suspended monolayer.pdf:application/pdf}
}


@article{Shi.2019,
 author = {Shi, Jia and Li, Yuanzheng and Zhang, Zhepeng and Feng, Weiqiang and Wang, Qi and Ren, Shuliang and Zhang, Jun and Du, Wenna and Wu, Xianxin and Sui, Xinyu and Mi, Yang and Wang, Rui and Sun, Yuanhui and Zhang, Lijun and Qiu, Xiaohui and Lu, Jiong and Shen, Chao and Zhang, Yanfeng and Zhang, Qing and Liu, Xinfeng},
 year = {2019},
 title = {Twisted-Angle-Dependent Optical Behaviors of Intralayer Excitons and Trions in WS$_2$/WSe$_2$ Heterostructure},
 pages = {3082--3091},
 volume = {6},
 number = {12},
 issn = {2330-4022},
 journal = {ACS Photonics},
 doi = {10.1021/acsphotonics.9b00855}
}



@article{bussolotti_impact_2021,
	title = {Impact of {S}-{Vacancies} on the {Charge} {Injection} {Barrier} at the {Electrical} {Contact} with the {MoS2} {Monolayer}},
	volume = {15},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.0c07982}            ,
	doi = {10.1021/acsnano.0c07982},
	abstract = {Making electrical contacts to semiconducting transition metal dichalcogenides (TMDCs) represents a major bottleneck for high device performance, often manifesting as strong Fermi level pinning and high contact resistance. Despite intense ongoing research, the mechanism by which lattice defects in TMDCs impact the transport properties across the contact–TMDC interface remains unsettled. Here we study the impact of S-vacancies on the electronic properties at a MoS2 monolayer interfaced with graphite by photoemission spectroscopy, where the defect density is selectively controlled by Ar sputtering. A clear reduction of the MoS2 core level and valence band binding energies is observed as the defect density increases. The experimental results are explained in terms of (i) gap states’ energy distribution and (ii) S-vacancies’ electrostatic disorder effect. Our model indicates that the Fermi level pinning at deep S-vacancy gap states is the origin of the commonly reported large electron injection barrier (∼0.5 eV) at the MoS2 ML interface with low work function metals. At the contact with high work function electrodes, S-vacancies do not significantly affect the hole injection barrier, which is intrinsically favored by Fermi level pinning at shallow occupied gap states. Our results clarify the importance of S-vacancies and electrostatic disorder in TMDC-based electronic devices, which could lead to strategies for optimizing device performance and production.},
	number = {2},
	urldate = {2025-03-03},
	journal = {ACS Nano},
	author = {Bussolotti, Fabio and Yang, Jing and Kawai, Hiroyo and Wong, Calvin Pei Yu and Goh, Kuan Eng Johnson},
	month = feb,
	year = {2021},
	pages = {2686--2697},
}

@article{khan_electronic_2017,
	title = {Electronic and Optical Properties of Vacancy Defects in Single-layer Transition Metal Dichalcogenides},
	volume = {95},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.95.245435}      ,
	doi = {10.1103/PhysRevB.95.245435},
	abstract = {A detailed first-principles study has been performed to evaluate the electronic and optical properties of single-layer (SL) transition metal dichalcogenides (TMDCs) (  ⁢  ⁢2;    = transition metal such as Mo, W, and    = S, Se, Te), in the presence of vacancy defects (VDs). Defects usually play an important role in tailoring electronic, optical, and magnetic properties of semiconductors. We consider three types of VDs in SL TMDCs: (i)    vacancy, (ii)   2 vacancy, and (iii)    vacancy. We show that VDs lead to localized defect states (LDS) in the band structure, which in turn gives rise to sharp transitions in in-plane and out-of-plane optical susceptibilities,   ∥ and   ⊥. The effects of spin-orbit coupling (SOC) are also considered. We find that SOC splitting in LDS is directly related to the atomic number of the transition metal atoms. Apart from electronic and optical properties we also find magnetic signatures (local magnetic moment of ∼    ) in MoSe2 in the presence of the Mo vacancy, which breaks the time-reversal symmetry and therefore lifts the Kramers degeneracy. We show that a simple qualitative tight-binding model (TBM), involving only the hopping between atoms surrounding the vacancy with an on-site SOC term, is sufficient to capture the essential features of LDS. In addition, the existence of the LDS can be understood from the solution of the two-dimensional Dirac Hamiltonian by employing infinite mass boundary conditions. In order to provide a clear description of the optical absorption spectra, we use group theory to derive the optical selection rules between LDS for both   ∥ and   ⊥.},
	number = {24},
	urldate = {2025-03-03},
	journal = {Phys. Rev. B},
	author = {Khan, M. A. and Erementchouk, Mikhail and Hendrickson, Joshua and Leuenberger, Michael N.},
	month = jun,
	year = {2017},
	pages = {245435},
}

@article{jeong_spectroscopic_2019,
	title = {Spectroscopic Studies of Atomic Defects and Bandgap Renormalization in Semiconducting Monolayer Transition Metal Dichalcogenides},
	volume = {10},
	copyright = {2019 The Author(s)},
	issn = {2041-1723},
	url = {https://www.nature.com/articles/s41467-019-11751-3},
	doi = {10.1038/s41467-019-11751-3},
	abstract = {Assessing atomic defect states and their ramifications on the electronic properties of two-dimensional van der Waals semiconducting transition metal dichalcogenides (SC-TMDs) is the primary task to expedite multi-disciplinary efforts in the promotion of next-generation electrical and optical device applications utilizing these low-dimensional materials. Here, with electron tunneling and optical spectroscopy measurements with density functional theory, we spectroscopically locate the mid-gap states from chalcogen-atom vacancies in four representative monolayer SC-TMDs—WS2, MoS2, WSe2, and MoSe2—, and carefully analyze the similarities and dissimilarities of the atomic defects in four distinctive materials regarding the physical origins of the missing chalcogen atoms and the implications to SC-mTMD properties. In addition, we address both quasiparticle and optical energy gaps of the SC-mTMD films and find out many-body interactions significantly enlarge the quasiparticle energy gaps and excitonic binding energies, when the semiconducting monolayers are encapsulated by non-interacting hexagonal boron nitride layers.},
	language = {en},
	number = {1},
	urldate = {2025-03-04},
	journal = {Nat. Commun.},
	author = {Jeong, Tae Young and Kim, Hakseong and Choi, Sang-Jun and Watanabe, Kenji and Taniguchi, Takashi and Yee, Ki Ju and Kim, Yong-Sung and Jung, Suyong},
	month = aug,
	year = {2019},
	keywords = {Condensed-matter physics, Materials for devices, Materials for optics, Materials science, Nanoscale materials},
	pages = {3825},
}

@article{cheiwchanchamnangij_quasiparticle_2012,
	title = {Quasiparticle Band Structure Calculation of Monolayer, Bilayer, and Bulk {MoS} 2},
	volume = {85},
	copyright = {http://link.aps.org/licenses/aps-default-license},
	issn = {1098-0121, 1550-235X},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.85.205302}   ,
	doi = {10.1103/PhysRevB.85.205302},
	language = {en},
	number = {20},
	urldate = {2025-03-04},
	journal = {Phys. Rev. B},
	author = {Cheiwchanchamnangij, Tawinan and Lambrecht, Walter R. L.},
	month = may,
	year = {2012},
	pages = {205302},
}

@article{chernikov_population_2015,
	title = {Population Inversion and Giant Bandgap Renormalization in Atomically Thin {WS$_2$} Layers},
	volume = {9},
	copyright = {2015 Springer Nature Limited},
	issn = {1749-4893},
	url = {https://www.nature.com/articles/nphoton.2015.104},
	doi = {10.1038/nphoton.2015.104},
	abstract = {Control of the optical properties of matter on ultrashort timescales is of both fundamental interest and central importance for applications in photonics. It is desirable to achieve pronounced changes over a broad spectral range using the least possible amount of material. Here, we demonstrate a dramatic change over a spectral range of hundreds of meV on the femtosecond timescale in the optical response of atomically thin two-dimensional crystals of the transition-metal dichalcogenide WS2 following excitation by intense optical pump pulses. Our findings reveal the role of extremely strong Coulomb interactions. At the direct gap, we observe a Mott transition from excitonic states to free carriers, accompanied by a giant bandgap renormalization of approximately 500 meV and the development of population inversion.},
	language = {en},
	number = {7},
	urldate = {2025-03-04},
	journal = {Nat. Photonics},
	author = {Chernikov, Alexey and Ruppert, Claudia and Hill, Heather M. and Rigosi, Albert F. and Heinz, Tony F.},
	month = jul,
	year = {2015},
	keywords = {Nonlinear optics},
	pages = {466--470},
}

@article{uddin_enhanced_2022,
	title = {Enhanced {Neutral} {Exciton} {Diffusion} in {Monolayer} {WS2} by {Exciton}–{Exciton} {Annihilation}},
	volume = {16},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.2c00956}    ,
	doi = {10.1021/acsnano.2c00956},
	abstract = {Dominant recombination pathways in monolayer transition metal dichalcogenides (TMDCs) depend primarily on background carrier concentration, generation rate, and applied strain. Charged excitons formed in the presence of background carriers mainly recombine nonradiatively. Neutral excitons recombine completely radiatively at low generation rates, but experience nonradiative exciton–exciton annihilation (EEA) at high generation rates. Strain can suppress EEA, resulting in near-unity photoluminescence quantum yield (PL QY) at all exciton densities. Although exciton diffusion is the primary channel of energy transport in excitonic materials and a critical optoelectronic design consideration, the combined effects of these factors on exciton diffusion are not clearly understood. In this work, we decouple the diffusion of neutral and charged excitons with chemical counterdoping and explore the effect of strain and generation rate on exciton diffusion. According to the standard semiconductor paradigm, a shorter carrier recombination lifetime should lead to a smaller diffusion length. Surprisingly, we find that increasing generation rate shortens the exciton lifetime but increases the diffusion length in unstrained monolayers of TMDCs. When we suppress EEA by strain, both lifetime and diffusion length become independent of generation rate. During EEA one exciton nonradiatively recombines and kinetically energizes another exciton, which then diffuses fast. Our results probe concentration-dependent diffusion of pure neutral excitons by counterdoping and elucidate how strain controls exciton transport and many-body interactions in TMDC monolayers.},
	number = {5},
	urldate = {2025-03-04},
	journal = {ACS Nano},
	author = {Uddin, Shiekh Zia and Higashitarumizu, Naoki and Kim, Hyungjin and Yi, Jun and Zhang, Xiang and Chrzan, Daryl and Javey, Ali},
	month = may,
	year = {2022},
	pages = {8005--8011},
}

@article{kumar_exciton-exciton_2014,
	title = {Exciton-exciton Annihilation in MoSe$_2$ Monolayers},
	volume = {89},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.89.125427}         ,
	doi = {10.1103/PhysRevB.89.125427},
	abstract = {We investigate the excitonic dynamics in MoSe2 monolayer and bulk samples by femtosecond transient absorption. Excitons are resonantly injected by a 750-nm and 100-fs laser pulse, and are detected by measuring a differential reflection of a probe pulse tuned in the range 790–820 nm. We observe a strong density-dependent initial decay of the exciton population in monolayers, which can be well described by the exciton-exciton annihilation. Such a feature is not observed in a bulk sample under comparable conditions. We also observe the saturated absorption induced by excitons in both monolayers and the bulk in the differential reflection measurements, which indicates their potential applications as saturable absorbers.},
	number = {12},
	urldate = {2025-03-04},
	journal = {Phys. Rev. B},
	author = {Kumar, Nardeep and Cui, Qiannan and Ceballos, Frank and He, Dawei and Wang, Yongsheng and Zhao, Hui},
	month = mar,
	year = {2014},
	pages = {125427},
}

@article{sun_observation_2014,
	title = {Observation of Rapid Exciton–Exciton Annihilation in Monolayer Molybdenum Disulfide},
	volume = {14},
	issn = {1530-6984},
	url = {https://doi.org/10.1021/nl5021975}         ,
	doi = {10.1021/nl5021975},
	abstract = {Monolayer MoS2 is a direct-gap two-dimensional semiconductor that exhibits strong electron–hole interactions, leading to the formation of stable excitons and trions. Here we report the existence of efficient exciton–exciton annihilation, a four-body interaction, in this material. Exciton–exciton annihilation was identified experimentally in ultrafast transient absorption measurements through the emergence of a decay channel varying quadratically with exciton density. The rate of exciton–exciton annihilation was determined to be (4.3 ± 1.1) × 10–2 cm2/s at room temperature.},
	number = {10},
	urldate = {2025-03-04},
	journal = {Nano Lett.},
	author = {Sun, Dezheng and Rao, Yi and Reider, Georg A. and Chen, Gugang and You, Yumeng and Brézin, Louis and Harutyunyan, Avetik R. and Heinz, Tony F.},
	month = oct,
	year = {2014},
	pages = {5625--5629},
}
% This file was created with Citavi 6.14.0.0

@article{Mak.2010,
 abstract = {The electronic properties of ultrathin crystals of molybdenum disulfide consisting of N=1,2,$\ldots$,6 S-Mo-S monolayers have been investigated by optical spectroscopy. Through characterization by absorption, photoluminescence, and photoconductivity spectroscopy, we trace the effect of quantum confinement on the material's electronic structure. With decreasing thickness, the indirect band gap, which lies below the direct gap in the bulk material, shifts upwards in energy by more than 0.6 eV. This leads to a crossover to a direct-gap material in the limit of the single monolayer. Unlike the bulk material, the MoS$_2$ monolayer emits light strongly. The freestanding monolayer exhibits an increase in luminescence quantum efficiency by more than a factor of 10$^4$ compared with the bulk material.},
 author = {Mak, Kin Fai and Lee, Changgu and Hone, James and Shan, Jie and Heinz, Tony F.},
 year = {2010},
 title = {Atomically Thin MoS$_2$: a New Direct-gap Semiconductor},
 pages = {136805},
 volume = {105},
 number = {13},
 journal = {Phys. Rev. Lett.},
 doi = {10.1103/PhysRevLett.105.136805}
}

@article{Gutierrez.2013,
 abstract = {Individual monolayers of metal dichalcogenides are atomically thin two-dimensional crystals with attractive physical properties different from those of their bulk counterparts. Here we describe the direct synthesis of WS2 monolayers with triangular morphologies and strong room-temperature photoluminescence (PL). The Raman response as well as the luminescence as a function of the number of S-W-S layers is also reported. The PL weakens with increasing number of layers due to a transition from direct band gap in a monolayer to indirect gap in multilayers. The edges of WS2 monolayers exhibit PL signals with extraordinary intensity, around 25 times stronger than that at the platelet's center. The structure and chemical composition of the platelet edges appear to be critical for PL enhancement.},
 author = {Guti{\'e}rrez, Humberto R. and Perea-L{\'o}pez, Nestor and El{\'i}as, Ana Laura and Berkdemir, Ayse and Wang, Bei and Lv, Ruitao and L{\'o}pez-Ur{\'i}as, Florentino and Crespi, Vincent H. and Terrones, Humberto and Terrones, Mauricio},
 year = {2013},
 title = {Extraordinary Room-Temperature Photoluminescence in Triangular WS$_2$ Monolayers},
 pages = {3447--3454},
 volume = {13},
 number = {8},
 issn = {1530-6984},
 journal = {Nano Lett.},
 doi = {10.1021/nl3026357},
 file = {Guti{\'e}rrez,:Attachments/Guti{\'e}rrez,.pdf:application/pdf}
}
@article{Xin.2022,
 abstract = {Defects, such as uncontrollable vacancies, will intensively degrade the material properties and device performance of CVD-grown transition metal dichalcogenides (TMDs). Although vacancies can be repaired by some post-processing measures, these treatments are usually time-consuming, complicated and may introduce uncontrollable chemical contaminants into TMDs. How to efficiently suppress the uncontrollable defects during CVD growth and acquire intrinsic high-quality CVD-grown TMDs without any after-treatment remains a critical challenge, and has not yet been well resolved. Here, an alternate-growth-etching (AGE) CVD method was demonstrated to fabricate defect-suppressed submillimeter-scale monolayer WS2 single crystals. Compared with normal CVD, the grain size of the as-grown WS2 can be enlarged by 4-5 times ($\sim$520 \textgreek{m}m) and the growth rate of $\sim$14.4 \textgreek{m}m min-1 is also at a high level compared to reported results. Moreover, AGE-CVD can efficiently suppress atomic vacancies in WS2. In every growth-etching cycle, the etching of WS2 occurs preferentially at the defective sites, which will be healed at the following growth stage. As a result, WS2 monolayers obtained by AGE-CVD possess higher crystal quality, carrier mobility (8.3 cm2 V-1 s-1) and PL quantum yield (QY, 52.6{\%}) than those by normal CVD. In particular, such a PL QY is the highest value ever reported for in situ CVD-grown TMDs without any after-treatment, and is even comparable to the values of mechanically exfoliated samples. This AGE-CVD method is also appropriate for the synthesis of other high-quality TMD single crystals on a large-scale.},
 author = {Xin, Xing and Zhang, Yanmei and Chen, Jiamei and Chen, Mao-Lin and Xin, Wei and Ding, Mengfan and Bao, Youzhe and Liu, Weizhen and Xu, Haiyang and Liu, Yichun},
 year = {2022},
 title = {Defect-Suppressed Submillimeter-Scale WS$_2$ Single Crystals with High Photoluminescence Quantum Yields by Alternate-Growth-Etching CVD},
 url = {https://pubs.rsc.org/en/content/articlelanding/2022/mh/d2mh00721e},
 pages = {2416--2424},
 volume = {9},
 number = {9},
 issn = {2051-6355},
 journal = {Mater. Horiz.},
 doi = {10.1039/D2MH00721E},
 file = {Xin, Zhang et al. 2022 - Defect-suppressed submillimeter-scale WS2 single crystals:Attachments/Xin, Zhang et al. 2022 - Defect-suppressed submillimeter-scale WS2 single crystals.pdf:application/pdf}
}
@article{Lee.2021,
 abstract = {Monolayer transition metal dichalcogenides (1L-TMDs) have tremendous potential as atomically thin, direct bandgap semiconductors that can be used as convenient building blocks for quantum photonic devices. However, the short exciton lifetime due to the defect traps and the strong exciton-exciton interaction in TMDs has significantly limited the efficiency of exciton emission from this class of materials. Here, we show that exciton-exciton interaction in 1L-WS2 can be effectively screened using an ultra-flat Au film substrate separated by multilayers of hexagonal boron nitride. Under this geometry, induced dipolar exciton-exciton interaction becomes quadrupole-quadrupole interaction because of effective image dipoles formed within the metal. The suppressed exciton-exciton interaction leads to a significantly improved quantum yield by an order of magnitude, which is also accompanied by a reduction in the exciton-exciton annihilation (EEA) rate, as confirmed by time-resolved optical measurements. A theoretical model accounting for the screening of the dipole-dipole interaction is in a good agreement with the dependence of EEA on exciton densities. Our results suggest that fundamental EEA processes in the TMD can be engineered through proximal metallic screening, which represents a practical approach towards high-efficiency 2D light emitters.},
 author = {Lee, Yongjun and Forte, Johnathas D'arf Severo and Chaves, Andrey and Kumar, Anshuman and Tran, Trang Thu and Kim, Youngbum and Roy, Shrawan and Taniguchi, Takashi and Watanabe, Kenji and Chernikov, Alexey and Jang, Joon I. and Low, Tony and Kim, Jeongyong},
 year = {2021},
 title = {Boosting Quantum Yields in Two-Dimensional Semiconductors via Proximal Metal Plates},
 url = {https://www.nature.com/articles/s41467-021-27418-x},
 pages = {7095},
 volume = {12},
 number = {1},
 issn = {2041-1723},
 journal = {Nat. Commun.},
 doi = {10.1038/s41467-021-27418-x},
 file = {Lee, Forte et al. 2021 - Boosting quantum yields in two-dimensional:Attachments/Lee, Forte et al. 2021 - Boosting quantum yields in two-dimensional.pdf:application/pdf}
}
@article{Kim.2021,
 abstract = {Most optoelectronic devices operate at high photocarrier densities, where all semiconductors suffer from enhanced nonradiative recombination. Nonradiative processes proportionately reduce photoluminescence (PL) quantum yield (QY), a performance metric that directly dictates the maximum device efficiency. Although transition metal dichalcogenide (TMDC) monolayers exhibit near-unity PL QY at low exciton densities, nonradiative exciton-exciton annihilation (EEA) enhanced by van-Hove singularity (VHS) rapidly degrades their PL QY at high exciton densities and limits their utility in practical applications. Here, by applying small mechanical strain (less than 1{\%}), we circumvented VHS resonance and markedly suppressed EEA in monolayer TMDCs, resulting in near-unity PL QY at all exciton densities despite the presence of a high native defect density. Our findings can enable light-emitting devices that retain high efficiency at all brightness levels.},
 author = {Kim, Hyungjin and Uddin, Shiekh Zia and Higashitarumizu, Naoki and Rabani, Eran and Javey, Ali},
 year = {2021},
 title = {Inhibited Nonradiative Decay at All Exciton Densities in Monolayer Semiconductors},
 pages = {448--452},
 volume = {373},
 number = {6553},
 journal = {Science},
 doi = {10.1126/science.abi9193},
 file = {Kim, Uddin et al. 2021 - Inhibited nonradiative decay at all:Attachments/Kim, Uddin et al. 2021 - Inhibited nonradiative decay at all.pdf:application/pdf}
}
@article{Andrzejewski.2020,
 abstract = {Advanced Optical Materials is a unique journal for materials science research which focuses on all aspects of light-matter interactions.},
 author = {Andrzejewski, Dominik and Oliver, Ruth and Beckmann, Yannick and Grundmann, Annika and Heuken, Michael and Kalisch, Holger and Vescan, Andrei and K{\"u}mmell, Tilmar and Bacher, Gerd},
 year = {2020},
 title = {Flexible Large--Area Light--Emitting Devices Based on WS$_2$ Monolayers},
 url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202000694}            ,
 pages = {2000694},
 volume = {8},
 number = {20},
 issn = {2195-1071},
 journal = {Adv. Opt. Mater.},
 doi = {10.1002/adom.202000694 },
 file = {Andrzejewski, Oliver et al. 2020 - Flexible Large-Area Light-Emitting Devices Based:Attachments/Andrzejewski, Oliver et al. 2020 - Flexible Large-Area Light-Emitting Devices Based.pdf:application/pdf}
}
@article{Hutten.2021,
 abstract = {Transfer-free, scalable photodetectors based on MOCVD-grown 2D-heterostructures, Ulrike Hutten, Leon Daniel, Annika Grundmann, Nicole Stracke, Mohamed Abdelbaky, Yannick Beckmann, Michael Heuken, Wolfgang Mertin, Holger Kalisch, Andrei Vescan, Gerd Bacher, Tilmar K{\"u}mmell},
 author = {Hutten, Ulrike and Daniel, Leon and Grundmann, Annika and Stracke, Nicole and Abdelbaky, Mohamed and Beckmann, Yannick and Heuken, Michael and Mertin, Wolfgang and Kalisch, Holger and Vescan, Andrei and Bacher, Gerd and K{\"u}mmell, Tilmar},
 year = {2021},
 title = {Transfer-free, Scalable Photodetectors Based on MOCVD-Grown 2D-Heterostructures},
 url = {https://iopscience.iop.org/article/10.1088/2053-1583/ac186d  }        ,
 pages = {045015},
 volume = {8},
 number = {4},
 issn = {2053-1583},
 journal = {2D Mater.},
 doi = {10.1088/2053-1583/ac186d },
 file = {Hutten, Daniel et al. 2021 - Transfer-free:Attachments/Hutten, Daniel et al. 2021 - Transfer-free.pdf:application/pdf}
}
% This file was created with Citavi 6.14.0.0

@article{Liu.2013,
 abstract = {Wavelength tunable semiconductor nanowire (NW) lasers are promising for multifunctional applications ranging from optical communication to spectroscopy analysis. Here, we present a demonstration of utilizing the surface plasmon polariton (SPP) enhanced Burstein-Moss (BM) effect to tune the lasing wavelength of a single semiconductor NW. The photonic lasing mode of the CdS NW (with length {\~{}}10 \textgreek{m}m and diameter {\~{}}220 nm) significantly blue shifts from 504 to 483 nm at room temperature when the NW is in close proximity to the Au film. Systematic steady state power dependent photoluminescence (PL) and time-resolved PL studies validate that the BM effect in the hybrid CdS NW devices is greatly enhanced as a consequence of the strong coupling between the SPP and CdS excitons. With decreasing dielectric layer thickness h from 100 to 5 nm, the enhancement of the BM effect becomes stronger, leading to a larger blue shift of the lasing wavelength. Measurements of enhanced exciton emission intensities and recombination rates in the presence of Au film further support the strong interaction between SPP and excitons, which is consistent with the simulation results.},
 author = {Liu, Xinfeng and Zhang, Qing and Yip, Jing Ngei and Xiong, Qihua and Sum, Tze Chien},
 year = {2013},
 title = {Wavelength Tunable Single Nanowire Lasers Based on Surface Plasmon Polariton Enhanced Burstein-Moss Effect},
 pages = {5336--5343},
 volume = {13},
 number = {11},
 journal = {Nano Lett.},
 doi = {10.1021/nl402836x }
}

@article{trovatello_ultrafast_2020,
	title = {The Ultrafast Onset of Exciton Formation in {2D} Semiconductors},
	volume = {11},
	copyright = {2020 The Author(s)},
	issn = {2041-1723},
	url = {https://www.nature.com/articles/s41467-020-18835-5},
	doi = {10.1038/s41467-020-18835-5},
	abstract = {The equilibrium and non-equilibrium optical properties of single-layer transition metal dichalcogenides (TMDs) are determined by strongly bound excitons. Exciton relaxation dynamics in TMDs have been extensively studied by time-domain optical spectroscopies. However, the formation dynamics of excitons following non-resonant photoexcitation of free electron-hole pairs have been challenging to directly probe because of their inherently fast timescales. Here, we use extremely short optical pulses to non-resonantly excite an electron-hole plasma and show the formation of two-dimensional excitons in single-layer MoS2 on the timescale of 30 fs via the induced changes to photo-absorption. These formation dynamics are significantly faster than in conventional 2D quantum wells and are attributed to the intense Coulombic interactions present in 2D TMDs. A theoretical model of a coherent polarization that dephases and relaxes to an incoherent exciton population reproduces the experimental dynamics on the sub-100-fs timescale and sheds light into the underlying mechanism of how the lowest-energy excitons, which are the most important for optoelectronic applications, form from higher-energy excitations. Importantly, a phonon-mediated exciton cascade from higher energy states to the ground excitonic state is found to be the rate-limiting process. These results set an ultimate timescale of the exciton formation in TMDs and elucidate the exceptionally fast physical mechanism behind this process.},
	language = {en},
	number = {1},
	urldate = {2025-03-18},
	journal = {Nat. Commun.},
	author = {Trovatello, Chiara and Katsch, Florian and Borys, Nicholas J. and Selig, Malte and Yao, Kaiyuan and Borrego-Varillas, Rocio and Scotognella, Francesco and Kriegel, Ilka and Yan, Aiming and Zettl, Alex and Schuck, P. James and Knorr, Andreas and Cerullo, Giulio and Conte, Stefano Dal},
	month = oct,
	year = {2020},
	keywords = {Optical spectroscopy, Two-dimensional materials},
	pages = {5277},
}



@article{yin_robust_2019,
	title = {Robust Trap Effect in Transition Metal Dichalcogenides for Advanced Multifunctional Devices},
	volume = {10},
	copyright = {2019 The Author(s)},
	issn = {2041-1723},
	url = {https://www.nature.com/articles/s41467-019-12200-x},
	doi = {10.1038/s41467-019-12200-x},
	abstract = {Defects play a crucial role in determining electric transport properties of two-dimensional transition metal dichalcogenides. In particular, defect-induced deep traps have been demonstrated to possess the ability to capture carriers. However, due to their poor stability and controllability, most studies focus on eliminating this trap effect, and little consideration was devoted to the applications of their inherent capabilities on electronics. Here, we report the realization of robust trap effect, which can capture carriers and store them steadily, in two-dimensional MoS2xSe2(1-x) via synergistic effect of sulphur vacancies and isoelectronic selenium atoms. As a result, infrared detection with very high photoresponsivity (2.4 × 105 A W−1) and photoswitching ratio ({\textasciitilde}108), as well as nonvolatile infrared memory with high program/erase ratio ({\textasciitilde}108) and fast switching time, are achieved just based on an individual flake. This demonstration of defect engineering opens up an avenue for achieving high-performance infrared detector and memory.},
	language = {en},
	number = {1},
	urldate = {2025-03-27},
	journal = {Nat. Commun.},
	author = {Yin, Lei and He, Peng and Cheng, Ruiqing and Wang, Feng and Wang, Fengmei and Wang, Zhenxing and Wen, Yao and He, Jun},
	month = sep,
	year = {2019},
	keywords = {Electronic devices, Two-dimensional materials},
	pages = {4133},
}

@article{kastl_effects_2019,
	title = {Effects of Defects on Band Structure and Excitons in WS$_2$ Revealed by Nanoscale Photoemission Spectroscopy},
	volume = {13},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.8b06574}    ,
	doi = {10.1021/acsnano.8b06574},
	abstract = {Two-dimensional materials with engineered composition and structure will provide designer materials beyond conventional semiconductors. However, the potentials of defect engineering remain largely untapped, because it hinges on a precise understanding of electronic structure and excitonic properties, which are not yet predictable by theory alone. Here, we utilize correlative, nanoscale photoemission spectroscopy to visualize how local introduction of defects modifies electronic and excitonic properties of two-dimensional materials at the nanoscale. As a model system, we study chemical vapor deposition grown monolayer WS2, a prototypical, direct gap, two-dimensional semiconductor. By cross-correlating nanoscale angle-resolved photoemission spectroscopy, core level spectroscopy, and photoluminescence, we unravel how local variations in defect density influence electronic structure, lateral band alignment, and excitonic phenomena in synthetic WS2 monolayers.},
	number = {2},
	urldate = {2025-03-27},
	journal = {ACS Nano},
	author = {Kastl, Christoph and Koch, Roland J. and Chen, Christopher T. and Eichhorn, Johanna and Ulstrup, Søren and Bostwick, Aaron and Jozwiak, Chris and Kuykendall, Tevye R. and Borys, Nicholas J. and Toma, Francesca M. and Aloni, Shaul and Weber-Bargioni, Alexander and Rotenberg, Eli and Schwartzberg, Adam M.},
	month = feb,
	year = {2019},
	pages = {1284--1291},
}


@article{pogna_photo-induced_2016,
	title = {Photo-{Induced} {Bandgap} {Renormalization} {Governs} the {Ultrafast} {Response} of {Single}-{Layer} {MoS$_2$}},
	volume = {10},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.5b06488}    ,
	doi = {10.1021/acsnano.5b06488},
	abstract = {Transition metal dichalcogenides (TMDs) are emerging as promising two-dimensional (2D) semiconductors for optoelectronic and flexible devices. However, a microscopic explanation of their photophysics, of pivotal importance for the understanding and optimization of device operation, is still lacking. Here, we use femtosecond transient absorption spectroscopy, with pump pulse tunability and broadband probing, to monitor the relaxation dynamics of single-layer MoS2 over the entire visible range, upon photoexcitation of different excitonic transitions. We find that, irrespective of excitation photon energy, the transient absorption spectrum shows the simultaneous bleaching of all excitonic transitions and corresponding red-shifted photoinduced absorption bands. First-principle modeling of the ultrafast optical response reveals that a transient bandgap renormalization, caused by the presence of photoexcited carriers, is primarily responsible for the observed features. Our results demonstrate the strong impact of many-body effects in the transient optical response of TMDs even in the low-excitation-density regime.},
	number = {1},
	urldate = {2025-03-24},
	journal = {ACS Nano},
	author = {Pogna, Eva A. A. and Marsili, Margherita and De Fazio, Domenico and Dal Conte, Stefano and Manzoni, Cristian and Sangalli, Davide and Yoon, Duhee and Lombardo, Antonio and Ferrari, Andrea C. and Marini, Andrea and Cerullo, Giulio and Prezzi, Deborah},
	month = jan,
	year = {2016},
	pages = {1182--1188},
}

@article{Mohammed_2016,
  author={Mohammed, Goran Abdulrahman and Hou, Ming},
  journal={IEEE Trans. Biomed. Eng.}, 
  title={Optimization of Active Muscle Force–Length Models Using Least Squares Curve Fitting}, 
  year={2016},
  volume={63},
  number={3},
  pages={630-635},
  keywords={Muscles;Force;Polynomials;Data models;Splines (mathematics);Frequency modulation;Biological system modeling;Muscle force-length relationship;least squares optimization;curve fitting;asymmetric Gaussian;Asymmetric Gaussian;curve fitting;least squares optimization;muscle force–length relationship},
  doi={10.1109/TBME.2015.2467169}}

@book{Tkachenko_2006,
author = {Tkachenko, Nikolai V.},
address = {Amsterdam ;},
booktitle = {Optical Spectroscopy : Methods and Instrumentations},
edition = {1st edition},
isbn = {0444521267},
keywords = {Optical spectroscopy ; Optical instruments -- Methodology},
language = {eng},
publisher = {Elsevier},
title = {Optical Spectroscopy : Methods and Instrumentations},
year = {2006},
pages = {293}
}


@article{kresse1996efficient,
        title = {Efficient Iterative Schemes for Ab Initio Total-Energy Calculations Using a Plane-Wave Basis Set},
	volume = {54},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.54.11169},
	doi = {10.1103/PhysRevB.54.11169},
	pages = {11169--11186},
	number = {16},
	journal = {Phys. Rev. B},
	author = {Kresse, G. and Furthmüller, J.},
	urldate = {2025-06-20},
	year = {1996},
}


@article{kresse1999ultrasoft,
	title = {From Ultrasoft Pseudopotentials to the Projector Augmented-Wave Method},
	volume = {59},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.59.1758},
	doi = {10.1103/PhysRevB.59.1758},
	pages = {1758--1775},
	number = {3},
	journal = {Phys. Rev. B},
	author = {Kresse, G. and Joubert, D.},
	urldate = {2025-06-20},
	year = {1999},
}

@article{blochl1994projector,
        title = {Projector Augmented-Wave Method},
	volume = {50},
	url = {https://link.aps.org/doi/10.1103/PhysRevB.50.17953},
	doi = {10.1103/PhysRevB.50.17953},
	pages = {17953--17979},
	number = {24},
	journal = {Phys. Rev. B},
	author = {Blöchl, P. E.},
	urldate = {2025-06-20},
	year = {1994},
}


@article{perdew1996generalized,
	title = {Generalized Gradient Approximation Made Simple},
	volume = {77},
	url = {https://link.aps.org/doi/10.1103/PhysRevLett.77.3865},
	doi = {10.1103/PhysRevLett.77.3865},
	pages = {3865--3868},
	number = {18},
	journal = {Phys. Rev. Lett.},
	author = {Perdew, John P. and Burke, Kieron and Ernzerhof, Matthias},
	urldate = {2025-06-20},
	year = {1996},
}


@article{lin2018realizing,
	title = {Realizing Large-Scale, Electronic-Grade Two-Dimensional Semiconductors},
	volume = {12},
	issn = {1936-0851},
	url = {https://doi.org/10.1021/acsnano.7b07059},
	doi = {10.1021/acsnano.7b07059},
	pages = {965--975},
	number = {2},
	journal = {ACS Nano},
	author = {Lin, Yu-Chuan and Jariwala, Bhakti and Bersch, Brian M. and Xu, Ke and Nie, Yifan and Wang, Baoming and Eichfeld, Sarah M. and Zhang, Xiaotian and Choudhury, Tanushree H. and Pan, Yi and Addou, Rafik and Smyth, Christopher M. and Li, Jun and Zhang, Kehao and Haque, M. Aman and Fölsch, Stefan and Feenstra, Randall M. and Wallace, Robert M. and Cho, Kyeongjae and Fullerton-Shirey, Susan K. and Redwing, Joan M. and Robinson, Joshua A.},
	urldate = {2025-06-20},
	year = {2018},
}


@article{Sleziona.2024,
 author = {Sleziona, Stephan and Kharsah, Osamah and Skopinski, Lucia and Daniel, Leon and Schmeink, Jennifer and Schleberger, Marika},
 year = {2024},
 title = {Influence of Highly Charged Ion Irradiation on the Electrical and Memory Properties of Black Phosphorus Field--Effect Transistors},
 issn = {2199-160X},
 journal = {Adv. Electron. Mater.},
volume = {n/a},
number = {n/a},
pages = {2400318},
 doi = {10.1002/aelm.202400318 },
 file = {Sleziona, Kharsah et al. 2024 - Influence of Highly Charged Ion:Attachments/Sleziona, Kharsah et al. 2024 - Influence of Highly Charged Ion.pdf:application/pdf}
}
@article{Sleziona.2023,
author = {S. Sleziona and A. Pelella and E. Faella and O. Kharsah and L. Skopinski and A. Maas and Y. Liebsch and J. Schmeink and A. Di Bartolomeo and M. Schleberger},
 year = {2019},
 title = {Manipulation of the Electrical and Memory Properties of MoS$_2$ Field-Effect Transistors by Highly Charged Ion Irradiation},
 pages = {6958},
 volume = {5},
 journal = {Nanoscale Adv.},
 doi = {10.1039/D3NA00543G }
}
@article{Pelella.2020,
 abstract = {Metal contacts play a fundamental role in nanoscale devices. In this work, Schottky metal contacts in monolayer molybdenum disulfide (MoS2) field-effect transistors are investigated under electron beam irradiation. It is shown that the exposure of Ti/Au source/drain electrodes to an electron beam reduces the contact resistance and improves the transistor performance. The electron beam conditioning of contacts is permanent, while the irradiation of the channel can produce transient effects. It is demonstrated that irradiation lowers the Schottky barrier at the contacts because of thermally induced atom diffusion and interfacial reactions. The simulation of electron paths in the device reveals that most of the beam energy is absorbed in the metal contacts. The study demonstrates that electron beam irradiation can be effectively used for contact improvement through local annealing.},
 author = {Pelella, Aniello and Kharsah, Osamah and Grillo, Alessandro and Urban, Francesca and Passacantando, Maurizio and Giubileo, Filippo and Iemmo, Laura and Sleziona, Stephan and Pollmann, Erik and Madau{\ss}, Lukas and Schleberger, Marika and {Di Bartolomeo}, Antonio},
 year = {2020},
 title = {Electron Irradiation of Metal Contacts in Monolayer MoS$_2$ Field-Effect Transistors},
 pages = {40532--40540},
 volume = {12},
 number = {36},
 issn = {1944-8244},
 journal = {ACS Appl. Mater. Interfaces},
 doi = {10.1021/acsami.0c11933 },
 file = {Pelella, Kharsah et al. 2020 - Electron Irradiation of Metal Contacts:Attachments/Pelella, Kharsah et al. 2020 - Electron Irradiation of Metal Contacts.pdf:application/pdf}
}
@article{Hopster.2013,
author = {J. Hopster and R. Kozubek and J. Krämer and V. Sokolovsky and M. Schleberger},
 year = {2013},
 title = {Ultra-thin MoS$_2$ Irradiated with Highly Charged Ions},
 pages = {165},
 volume = {317},
 journal = {Nucl. Instr. Meth. B},
 doi = {10.1016/j.nimb.2013.02.038 }
}
@article{Madauss.2017,
author = {L. Madauß and O. Ochedowski and H. Lebius and B. Ban-d'Etat and C. Naylor and A. Johnson and J. Kotakoski and M. Schleberger},
 year = {2017},
 title = {Defect Engineering of Single- and Few-layer MoS$_2$ by Swift Heavy Ion Irradiation 2D Materials},
 pages = {015034},
 volume = {4},
 journal = {2D Mater.},
 doi = {10.1088/2053-1583/4/1/015034 }
}
@article{Schleberger.2018,
author = {M. Schleberger and J. Kotakoski},
 year = {2018},
 title = {2D Material Science: Defect Engineering by Particle Irradiation},
 pages = {1885},
 volume = {11},
 journal = {Materials},
 doi = {10.3390/ma11101885 }
}
@article{Kozubek.2019,
author = {R. Kozubek and M. Tripathi and M. Ghorbani-Asl and S. Kretschmer and L. Madauß and E. Pollmann and M. O´Brien and N. McEvoy and U. Ludacka and T. Susi and G. Duesberg and R.A. Wilhelm and A.V. Krasheninnikov and J. Kotakoski and M. Schleberger},
 year = {2019},
 title = {Perforationg Freestanding Molybdenum Disulfide Monolayers with Highly Charged Ions},
 pages = {904},
 volume = {10},
 journal = {J. Phys. Chem. Lett.},
 doi = {10.1021/acs.jpclett.8b03666 }
}
@article{Asaithambi.2021,
 abstract = {Tungsten disulfide is one of the prominent transition metal dichalcogenide materials, which shows a transition from an indirect to a direct bandgap as the layer thickness is reduced down to a monol...},
 author = {Asaithambi, Aswin and Kozubek, Roland and Prinz, G{\"u}nther M. and Reale, Francesco and Pollmann, Erik and Ney, Marcel and Mattevi, Cecilia and Schleberger, Marika and Lorke, Axel},
 year = {2021},
 title = {Laser-- and Ion--Induced Defect Engineering in WS$_2$ Monolayers},
 url = {https://onlinelibrary.wiley.com/doi/full/10.1002/pssr.202000466     }                    , 
 pages = {2000466},
 volume = {15},
 number = {1},
 issn = {1862-6254},
 journal = {Phys. Status Solidi RRL},
 doi = {10.1002/pssr.202000466 },
 file = {Asaithambi, Kozubek et al. 2021 - Laser- and Ion-Induced Defect Engineering:Attachments/Asaithambi, Kozubek et al. 2021 - Laser- and Ion-Induced Defect Engineering.pdf:application/pdf}
}
@article{Pollmann.2020,
 abstract = {Innovative applications based on two-dimensional solids require cost-effective fabrication processes resulting in large areas of high quality materials. Chemical vapour deposition is among the most promising methods to fulfill these requirements. However, for 2D materials prepared in this way it is generally assumed that they are of inferior quality in comparison to the exfoliated 2D materials commonly used in basic research. In this work we challenge this assumption and aim to quantify the differences in quality for the prototypical transition metal dichalcogenide MoS2. To this end single layers of MoS2 prepared by different techniques (exfoliation, grown by different chemical vapour deposition methods, transfer techniques and as vertical heterostructure with graphene) are studied by Raman and photoluminescence spectroscopy, complemented by atomic force microscopy. We demonstrate that as-prepared MoS2, directly grown on SiO2, differs from exfoliated MoS2 in terms of higher photoluminescence, lower electron concentration and increased strain. As soon as a water film is intercalated (e.g. by transfer) underneath the grown MoS2, in particular the (opto)electronic properties become practically identical to those of exfoliated MoS2. A comparison of the two most common precursors shows that the growth with MoO3 causes greater strain and/or defect density deviations than growth with ammonium heptamolybdate. As part of a heterostructure directly grown MoS2 interacts much stronger with the substrate and in this case an intercalated water film does not lead to the complete decoupling, which is typical for exfoliation or transfer. Our work shows that the supposedly poorer quality of grown 2D transition metal dichalcogenides is indeed a misconception.},
 author = {Pollmann, Erik and Madau{\ss}, Lukas and Schumacher, Simon and Kumar, Uttam and Heuvel, Flemming and {vom Ende}, Christina and Yilmaz, S{\"u}meyra and G{\"u}ng{\"o}rm{\"u}s, S{\"u}meyra and Schleberger, Marika},
 year = {2020},
 title = {Apparent Differences Between Single Layer Molybdenum Disulphide Fabricated via Chemical Vapour Deposition and Exfoliation},
 pages = {505604},
 volume = {31},
 number = {50},
 journal = {Nanotechnology},
 doi = {10.1088/1361-6528/abb5d2},
 file = {Pollmann, Madau{\ss} et al. 2020 - Apparent differences between single layer:Attachments/Pollmann, Madau{\ss} et al. 2020 - Apparent differences between single layer.pdf:application/pdf}
}
