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Title: Electronic and thermoelectric properties of few-layer transition metal dichalcogenides

The electronic and thermoelectric properties of one to four monolayers of MoS{sub 2}, MoSe{sub 2}, WS{sub 2}, and WSe{sub 2} are calculated. For few layer thicknesses, the near degeneracies of the conduction band K and Σ valleys and the valence band Γ and K valleys enhance the n-type and p-type thermoelectric performance. The interlayer hybridization and energy level splitting determine how the number of modes within k{sub B}T of a valley minimum changes with layer thickness. In all cases, the maximum ZT coincides with the greatest near-degeneracy within k{sub B}T of the band edge that results in the sharpest turn-on of the density of modes. The thickness at which this maximum occurs is, in general, not a monolayer. The transition from few layers to bulk is discussed. Effective masses, energy gaps, power-factors, and ZT values are tabulated for all materials and layer thicknesses.
Authors:
;  [1] ;  [2]
  1. Department of Electrical Engineering, University of California, Riverside, California 92521-0204 (United States)
  2. Department of Physics and the Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong SAR (China)
Publication Date:
OSTI Identifier:
22253364
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; DENSITY; ENERGY GAP; ENERGY LEVELS; HYBRIDIZATION; LAYERS; MOLYBDENUM SELENIDES; MOLYBDENUM SULFIDES; POWER FACTOR; THERMOELECTRIC PROPERTIES; THICKNESS; TRANSITION ELEMENTS; TUNGSTEN SULFIDES