Journal ArticleDOI
Broad-range modulation of light emission in two-dimensional semiconductors by molecular physisorption gating.
Sefaattin Tongay,Jian Zhou,Can Ataca,Jonathan Liu,Jeong Seuk Kang,Tyler S. Matthews,Long You,Jingbo Li,Jeffrey C. Grossman,Junqiao Wu,Junqiao Wu +10 more
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TLDR
Physi-sorbed O2 and/or H2O molecules electronically deplete n-type materials such as MoS2 and MoSe2, which weakens electrostatic screening that would otherwise destabilize excitons, leading to the drastic enhancement in photoluminescence.Abstract:
In the monolayer limit, transition metal dichalcogenides become direct-bandgap, light-emitting semiconductors. The quantum yield of light emission is low and extremely sensitive to the substrate used, while the underlying physics remains elusive. In this work, we report over 100 times modulation of light emission efficiency of these two-dimensional semiconductors by physical adsorption of O2 and/or H2O molecules, while inert gases do not cause such effect. The O2 and/or H2O pressure acts quantitatively as an instantaneously reversible “molecular gating” force, providing orders of magnitude broader control of carrier density and light emission than conventional electric field gating. Physi-sorbed O2 and/or H2O molecules electronically deplete n-type materials such as MoS2 and MoSe2, which weakens electrostatic screening that would otherwise destabilize excitons, leading to the drastic enhancement in photoluminescence. In p-type materials such as WSe2, the molecular physisorption results in the opposite eff...read more
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Suppression of Defects and Deep Levels Using Isoelectronic Tungsten Substitution in Monolayer MoSe2
Xufan Li,Alexander A. Puretzky,Xiahan Sang,Santosh Kc,Mengkun Tian,Frank Ceballos,Masoud Mahjouri-Samani,Kai Wang,Raymond R. Unocic,Hui Zhao,Gerd Duscher,Valentino R. Cooper,Christopher M. Rouleau,David B. Geohegan,Kai Xiao +14 more
TL;DR: In this paper, isoelectronic doping is presented as a new strategy to form stable alloys and suppress defects and enhance photoluminescence (PL) in CVD-grown TMD monolayers.
Journal ArticleDOI
CVD synthesis of Mo(1−x)WxS2 and MoS2(1−x)Se2x alloy monolayers aimed at tuning the bandgap of molybdenum disulfide
TL;DR: For the first time, a one-step CVD strategy is reported for the growth of ternary alloy Mo(1-x)WxS2 monolayers (ML) on SiO2/Si substrates with controllable composition to reveal the important role of alloying in tailoring the electronic structure of 2D materials.
Journal ArticleDOI
P-type Doping in Large-Area Monolayer MoS2 by Chemical Vapor Deposition.
Mengge Li,Jiadong Yao,Xiaoxiang Wu,Shucheng Zhang,Boran Xing,Xinyue Niu,Xiaoyuan Yan,Ying Yu,Yali Liu,Yewu Wang,Yewu Wang +10 more
TL;DR: Electrical measurements indicate Nb-doping suppresses n-type conductivity in MoS2 and shows an ambipolar transport behavior after annealing under sulfur atmosphere, which highlights the p-type doping effect via Nb, corresponding to the density functional theory (DFT) calculations with Fermi-level shifting to valance band maximum.
Journal ArticleDOI
Charge Versus Energy Transfer in Atomically Thin Graphene-Transition Metal Dichalcogenide van der Waals Heterostructures
TL;DR: In this paper, an experimental study of a van der Waals heterostructures (vdWHs) is presented, which reveals details of these dynamics that will be essential for future designs of devices based on vdWHs.
Journal ArticleDOI
Air Passivation of Chalcogen Vacancies in Two-Dimensional Semiconductors
TL;DR: In this paper, the authors study the interaction between air and chalcogen vacancies (V(X)), the most typical defects in 2D semiconductors, and propose an approach to improve the performance of 2D SCs by using air/O2 to passivate the defects.
References
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Journal ArticleDOI
Generalized Gradient Approximation Made Simple
TL;DR: A simple derivation of a simple GGA is presented, in which all parameters (other than those in LSD) are fundamental constants, and only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked.
Journal ArticleDOI
Projector augmented-wave method
TL;DR: An approach for electronic structure calculations is described that generalizes both the pseudopotential method and the linear augmented-plane-wave (LAPW) method in a natural way and can be used to treat first-row and transition-metal elements with affordable effort and provides access to the full wave function.
Journal ArticleDOI
Ab initio molecular dynamics for liquid metals.
Georg Kresse,Jürgen Hafner +1 more
TL;DR: In this paper, the authors present an ab initio quantum-mechanical molecular-dynamics calculations based on the calculation of the electronic ground state and of the Hellmann-Feynman forces in the local density approximation.
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Semiempirical GGA-type density functional constructed with a long-range dispersion correction.
TL;DR: A new density functional of the generalized gradient approximation (GGA) type for general chemistry applications termed B97‐D is proposed, based on Becke's power‐series ansatz from 1997, and is explicitly parameterized by including damped atom‐pairwise dispersion corrections of the form C6 · R−6.
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Atomically thin MoS2: a new direct-gap semiconductor
TL;DR: The electronic properties of ultrathin crystals of molybdenum disulfide consisting of N=1,2,…,6 S-Mo-S monolayers have been investigated by optical spectroscopy and the effect of quantum confinement on the material's electronic structure is traced.