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Title: Thermoelectric properties of chalcopyrite type CuGaTe{sub 2} and chalcostibite CuSbS{sub 2}

Electronic and transport properties of CuGaTe{sub 2}, a hole-doped ternary copper based chalcopyrite type semiconductor, are studied using calculations within the Density Functional Theory and solving the Boltzmann transport equation within the constant relaxation time approximation. The electronic band structures are calculated by means of the full-potential linear augmented plane wave method, using the Tran-Blaha modified Becke-Johnson potential. The calculated band gap of 1.23 eV is in agreement with the experimental value of 1.2 eV. The carrier concentration- and temperature dependent thermoelectric properties of CuGaTe{sub 2} are derived, and a figure of merit of zT = 1.69 is obtained at 950 K for a hole concentration of 3.7·10{sup 19} cm{sup −3}, in agreement with a recent experimental finding of zT = 1.4, confirming that CuGaTe{sub 2} is a promising material for high temperature thermoelectric applications. The good thermoelectric performance of p-type CuGaTe{sub 2} is associated with anisotropic transport from a combination of heavy and light bands. Also for CuSbS{sub 2} (chalcostibite), a better performance is obtained for p-type than for n-type doping. The variation of the thermopower as a function of temperature and concentration suggests that CuSbS{sub 2} will be a good thermoelectric material at low temperatures, similarly to the isostructural CuBiS{sub 2} compound.
Authors:
;  [1] ;  [2] ; ;  [3]
  1. Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502 205, Andhra Pradesh (India)
  2. Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500 046, Andhra Pradesh (India)
  3. Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)
Publication Date:
OSTI Identifier:
22266158
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 22; Other Information: (c) 2013 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; ABUNDANCE; ANISOTROPY; BOLTZMANN EQUATION; CHALCOPYRITE; CONCENTRATION RATIO; COPPER; DENSITY FUNCTIONAL METHOD; DOPED MATERIALS; PERFORMANCE; RELAXATION TIME; SEMICONDUCTOR MATERIALS; TEMPERATURE DEPENDENCE; THERMOELECTRIC MATERIALS; THERMOELECTRIC PROPERTIES; WAVE PROPAGATION