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Title: Increased p-type conductivity in GaN{sub x}Sb{sub 1−x}, experimental and theoretical aspects

The large increase in the p-type conductivity observed when nitrogen is added to GaSb has been studied using positron annihilation spectroscopy and ab initio calculations. Doppler broadening measurements have been conducted on samples of GaN{sub x}Sb{sub 1−x} layers grown by molecular beam epitaxy, and the results have been compared with calculated first-principle results corresponding to different defect structures. From the calculated data, binding energies for nitrogen-related defects have also been estimated. Based on the results, the increase in residual hole concentration is explained by an increase in the fraction of negative acceptor-type defects in the material. As the band gap decreases with increasing N concentration, the ionization levels of the defects move closer to the valence band. Ga vacancy-type defects are found to act as positron trapping defects in the material, and the ratio of Ga vacancy-type defects to Ga antisites is found to be higher than that of the p-type bulk GaSb substrate. Beside Ga vacancies, the calculated results imply that complexes of a Ga vacancy and nitrogen could be present in the material.
Authors:
; ; ; ;  [1] ;  [2] ;  [3]
  1. Department of Applied Physics, Aalto University, P.O. Box 14100, FIN-00076 Aalto Espoo (Finland)
  2. Department of Physics and Stephenson Institute for Renewable Energy, University of Liverpool, Liverpool L69 7ZF (United Kingdom)
  3. Department of Chemistry, University of Warwick, Coventry CV4 7AL (United Kingdom)
Publication Date:
OSTI Identifier:
22494814
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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANNIHILATION; BINDING ENERGY; COMPARATIVE EVALUATIONS; CONCENTRATION RATIO; DEFECTS; DOPPLER BROADENING; EXPERIMENT RESULTS; GALLIUM ANTIMONIDES; GALLIUM NITRIDES; HOLES; MOLECULAR BEAM EPITAXY; NITROGEN; POSITRONS; P-TYPE CONDUCTORS; SPECTROSCOPY; VALENCE