We have investigated the electronic structures of bulk GaSe and GaTe as well as the nature of defect states associated with substitutional impurities and vacancies in GaSe and GaTe. These calculations were done using <i>ab initio</i> density functional theory and supercell models. We find that the Ga-Ga dimers play an important role in the formation of defect states. Analysis of the charge densities and the band structures associated with the defect states indicates that they are strongly localized. Theoretical results are in good agreement with experiment for Cd_Ga and V_Ga in GaSe and for V_Ga in GaTe. The effect of spin-orbit interaction on the band structure of GaTe has been investigated; it is found that the top valence bands at the Γ-point shift up in energy by ~ 0.1 eV due to the mixing of Te p_x-p_y and p_z bands.

Date Published: 4 September 2008
PDF: 12 pages
Proc. SPIE 7079, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics X, 70790Q (4 September 2008); doi: 10.1117/12.796229

Published in SPIE Proceedings Vol. 7079:
Hard X-Ray, Gamma-Ray, and Neutron Detector Physics X
Arnold Burger; Larry A. Franks; Ralph B. James, Editor(s)