Determination of scattering time and of valley occupation in transition-metal dichalcogenides doped by field effect

Abstract

The transition-metal dichalcogenides have attracted a lot of attention as a possible stepping-stone toward atomically thin and flexible field-effect transistors. One key parameter to describe the charge transport is the time between two successive scattering events - the transport scattering time. In a recent report, we have shown that it is possible to use density functional theory to obtain the band structure of two-dimensional semiconductors in presence of field effect doping. Here, we report a simple method to extract the scattering time from the experimental conductivity and from the knowledge of the band structure. We apply our approach to monolayers and multilayers of MoS${}_2$, MoSe${}_2$, MoTe${}_2$, WS${}_2$, and WSe${}_2$ in presence of a gate. In WS${}_2$, for which accurate measurements of mobility have been published, we find that the scattering time is inversely proportional to the density of states at the Fermi level. Finally, we show that it is possible to identify the critical doping at which different valleys start to be occupied from the doping-dependence of the conductivity.

7 figures on 7 pages, accepted for publication in PRB

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• Electron and Hole Mobilities in Single-Layer WSe2
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• Electrochemical doping of few layer ZrNCl from first-principles: electronic and structural properties in field-effect configuration

Cited by in corpus (8)

• Multi-Valley Superconductivity In Ion-Gated MoS2 Layers
• Band filling and cross quantum capacitance in ion gated semiconducting transition metal dichalcogenide monolayers
• Tunable topological Nernst effect in 2D transition metal dichalcogenides
• Mapping multi-valley Lifshitz transitions induced by field-effect doping in strained MoS2 nanolayers
• Ionic gating in metallic superconductors: A brief review
• Orientation-dependent electric transport and band filling in hole co-doped epitaxial diamond films
• Migdal-Eliashberg theory of multi-band high-temperature superconductivity in field-effect-doped hydrogenated (111) diamond
• Strong band-filling-dependence of the scattering lifetime in gated MoS2 nanolayers induced by the opening of intervalley scattering channels