Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5-3 cm(2) V(-1) s(-1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS(2) mobility of at least 200 cm(2) V(-1) s(-1), similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on/off ratios of 1 × 10(8) and ultralow standby power dissipation. 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. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.

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Single-layer MoS2 transistors

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

Novel physical phenomena can emerge in low-dimensional nanomaterials. Bulk MoS2, a prototypical metal dichalcogenide, is an indirect bandgap semiconductor with negligible photoluminescence. When the MoS2 crystal is thinned to monolayer, however, a strong photoluminescence emerges, indicating an indirect to direct bandgap transition in this d-electron system. This observation shows that quantum confinement in layered d-electron materials like MoS2 provides new opportunities for engineering the electronic structure of matter at the nanoscale.

Emerging Photoluminescence in Monolayer MoS2

TiO2 photocatalysis and related surface phenomena

Infrared thermoreflectance of VχTi1-χSe2

Photoelectrochemical characterization of a rhenium octahedral cluster compound [Re6Se7Br4]

Scanning tunneling spectroscopy of the Abrikosov flux lattice from the clean toward the dirty limit

Presents a synchrotron radiation photoemission study of the upper-valence-band states of four ZrSe3-structure compounds: ZrS3, ZrSe3, ZrTe3 and HfSe3. The sulphide and selenide spectra exhibit a characteristic five-peak structure in agreement with the calculated ZrSe3 density of states by Myron et al. (1981) and by Bullett (1979). The nature of these features is established by an interplay between the rehybridization of paired-anion ligand orbitals and the hybridization of unpaired-anion states with cation states. The spectrum of ZrTe3 exhibits only three peaks that appear related to three of the sulphide and selenide spectral features. The differences between the sulphide, selenide spectra and the telluride spectra are discussed in terms of the very large distance between paired-anion ligands and neighbour cations in the latter compound

Francis Lévy

Papers

Infrared thermoreflectance of VχTi1-χSe2

Photoelectrochemical characterization of a rhenium octahedral cluster compound [Re6Se7Br4]

Scanning tunneling spectroscopy of the Abrikosov flux lattice from the clean toward the dirty limit

Photoemission experiments on the valence band of transition metal trichalcogenides

Refractive Index of GaS in the Far Infrared