Atomically thin MoS2: a new direct-gap semiconductor
TLDR
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.Abstract:
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 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 06 eV This leads to a crossover to a direct-gap material in the limit of the single monolayer Unlike the bulk material, the MoS₂ monolayer emits light strongly The freestanding monolayer exhibits an increase in luminescence quantum efficiency by more than a factor of 10⁴ compared with the bulk materialread more
Citations
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Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.
TL;DR: This work reviews the historical development of Transition metal dichalcogenides, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.
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Single-layer MoS2 transistors
TL;DR: Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors, and could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.
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Van der Waals heterostructures
TL;DR: With steady improvement in fabrication techniques and using graphene’s springboard, van der Waals heterostructures should develop into a large field of their own.
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The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets
TL;DR: This Review describes how the tunable electronic structure of TMDs makes them attractive for a variety of applications, as well as electrically active materials in opto-electronics.
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Phosphorene: An Unexplored 2D Semiconductor with a High Hole Mobility
TL;DR: In this paper, the 2D counterpart of layered black phosphorus, which is called phosphorene, is introduced as an unexplored p-type semiconducting material and the authors find that the band gap is direct, depends on the number of layers and the in-layer strain, and significantly larger than the bulk value of 0.31-0.36 eV.
References
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Electronic structure of MoSe2, MoS2, and WSe2. II. The nature of the optical band gaps
TL;DR: From band-structure calculations it is shown that MoSe2, MoS2, and WSe2 are indirect-gap semiconductors, and the wave function at the top of the valence band is shown to be a metal-nonmetal antibonding state, which explains the observed high stability of these materials in photoelectrochemical cells against photocorrosion.
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Kramers-Kronig analysis of the reflectivity spectra of 2H-MoS2, 2H-MoSe2 and 2H-MoTe2
A R Beal,H P Hughes +1 more
TL;DR: By extrapolating to 0 and 30 eV experimental data in the energy range from approximately 1-1.3 to 14 eV, a Kramers-Kronig analysis of the reflectivity spectrum at room temperature from the basal plane (E perpendicular to c) of single crystals of 2H-MoS2, 2HMoSe2 and 2H -MoTe2 has been performed.
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The band structures of some transition metal dichalcogenides. III. Group VIA: trigonal prism materials
R A Bromley,R B Murray,A D Yoffe +2 more
TL;DR: In this paper, the semi-empirical tight binding method is applied to the calculation of the electronic band structures of MoS2, MoSe2, alpha -MoTe2, WS2 and WSe2 in a two dimensional approximation.
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Transmission spectra of some transition metal dichalcogenides. II. Group VIA: trigonal prismatic coordination
A R Beal,J C Knights,W Y Liang +2 more
TL;DR: In this article, the transmission spectra of the layer type group VIA transition metal dichalcogenides have been measured at liquid helium temperature and sharpening of previously reported features have been found in addition to a great deal of new fine structure not reported in earlier work.
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The evolution of electronic structure in few-layer graphene revealed by optical spectroscopy
TL;DR: Using the Kubo formula, it is found that the complete infrared conductivity spectra for the different FLG crystals can be reproduced reasonably well within the framework a tight-binding model.