Effect of vacancies on the structure and properties of Ga2(Se0.33Te0.67)3

Ga2(Se0.33Te0.67)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 Ga2(Se0.33Te0.67)3 structure is investigated via...

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Bibliographic Details
Published in:Journal of applied physics 2015-08, Vol.118 (8)
Main Authors: Abdul-Jabbar, N. M., Forrest, T. R., Gronsky, R., Bourret-Courchesne, E. D., Wirth, B. D.
Format: Article
Language:English
Subjects:
Absorption spectra
Applied physics
Band gap
Carrier mobility
Computer memory
Current carriers
Energy gap
Fine structure
Hall effect
Material properties
Microscopy
Phase transitions
Synchrotron radiation
Vacancies
X ray absorption
X-ray diffraction
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Summary:Ga2(Se0.33Te0.67)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 Ga2(Se0.33Te0.67)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 Ga2(Se0.33Te0.67)3 is highly dependent on thermal annealing. It is posited that stoichiometric vacancies play a role in local atomic distortions in Ga2(Se0.33Te0.67)3 (based on the fine structure signals in the collected x-ray absorption spectra). The effect of vacancy ordering on Ga2(Se0.33Te0.67)3 material properties is also examined through band gap and Hall effect measurements, which reveal that the Ga2(Se0.33Te0.67)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.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4928812