Variation of band bending at the surface of Mg-doped InGaN: Evidence of p-type conductivity across the composition range

P. D. C. King, T. D. Veal, P. H. Jefferson, C. F. McConville, Hai Lu, W. J. Schaff

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)

Abstract

The variation of band bending as a function of composition at oxidized (0001) surfaces of Mg-doped InxGa1-xN is investigated using x-ray photoelectron spectroscopy. Distinctly different trends in barrier height are seen for the Mg-doped compared to undoped alloys, which is explained in terms of Fermi-level pinning at the surface and virtual gap states. Solutions of Poisson's equation within the modified Thomas-Fermi approximation are used to model the band bending and corresponding variation of carrier concentration with depth below the surface. A transition from a surface inversion layer for In-rich alloys to a surface hole depletion layer for Ga-rich alloys occurs at x approximate to 0.49. The trend in barrier height, calculated space-charge profiles, and difference of barrier height for undoped and Mg-doped InN indicate that Mg doping induces bulk p-type conductivity across the entire composition range.

Original languageEnglish
Pages (from-to)115312
Number of pages7
JournalPhysical Review. B, Condensed matter and materials physics
Volume75
Issue number11
DOIs
Publication statusPublished - Mar 2007

Keywords

  • PHASE-SEPARATION
  • IN1-XGAXN ALLOYS
  • INN SURFACES
  • GAP
  • LAYERS
  • DEPENDENCE
  • INXGA1-XN
  • INVERSION
  • NITRIDE

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