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Title: Effect of vacancies on the structure and properties of Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3}

Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} belongs to a family of materials with large intrinsic vacancy concentrations that are being actively studied due to their potential for diverse applications that include thermoelectrics and phase-change memory. In this article, the Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} structure is investigated via synchrotron x-ray diffraction, electron microscopy, and x-ray absorption experiments. Diffraction and microscopy measurements showed that the extent of vacancy ordering in Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} is highly dependent on thermal annealing. It is posited that stoichiometric vacancies play a role in local atomic distortions in Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} (based on the fine structure signals in the collected x-ray absorption spectra). The effect of vacancy ordering on Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} material properties is also examined through band gap and Hall effect measurements, which reveal that the Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} band gap redshifts by ≈0.05 eV as the vacancies order and accompanied by gains in charge carrier mobility. The results serve as an encouraging example of altering material properties via intrinsic structural rearrangement as opposed to extrinsic means, such as doping.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [2] ;  [4] ;  [5] ;  [1] ;  [2]
  1. Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States)
  2. (United States)
  3. European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France)
  4. Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States)
  5. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
22494813
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 8; Other Information: (c) 2015 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; ABSORPTION SPECTRA; ABUNDANCE; ANNEALING; CARRIER MOBILITY; CHARGE CARRIERS; ELECTRON MICROSCOPY; EV RANGE; FINE STRUCTURE; GALLIUM COMPLEXES; HALL EFFECT; RED SHIFT; STOICHIOMETRY; VACANCIES; X-RAY DIFFRACTION; X-RAY SPECTRA