Increased p-type conductivity in GaNxSb1-x, experimental and theoretical aspects

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Researchers

Research units

  • University of Liverpool
  • University of Warwick

Abstract

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 GaNxSb1-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. (C) 2015 AIP Publishing LLC.

Details

Original languageEnglish
Article number085708
Pages (from-to)1-9
Number of pages9
JournalJournal of Applied Physics
Volume118
Issue number8
Publication statusPublished - 28 Aug 2015
MoE publication typeA1 Journal article-refereed

    Research areas

  • POSITRON LIFETIME SPECTROSCOPY, UNDOPED GALLIUM ANTIMONIDE, MOLECULAR-BEAM EPITAXY, AUGMENTED-WAVE METHOD, BAND-GAP REDUCTION, GROWN GANAS, ALLOYS, PHOTOLUMINESCENCE, ANNIHILATION, SEMICONDUCTORS

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