P- and N-type Doping of Non-Polar A-plane GaN Grown by Molecular-Beam Epitaxy on R-plane Sapphire


R. Armitage, Qing Yang, Eicke R. Weber
Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720

This article was received on Sunday, August 3, 2003 and accepted on Wednesday, September 3, 2003.

Abstract

Non-polar a-plane GaN films doped with Si or Mg were grown by plasma-assisted molecular-beam epitaxy on r-plane sapphire substrates. The (11(-2)0) orientation of the GaN epilayers was confirmed by x-ray diffraction. The layers were further characterized by atomic force microscopy, Hall effect, and photoluminescence measurements. The Mg-doped layers showed p-type conductivity, with a maximum hole concentration of 6x1017 cm-3 (µ = 2 cm2/Vs). Comparison with Mg-doping of N-polar c-plane GaN suggests the Mg sticking coefficient may be higher on the GaN (11(-2)0) surface compared to the GaN (000(-1)) surface. The electron mobility obtained for a-plane GaN:Si (18 cm2/Vs for n = 1x1018 cm-3) was low compared to that of typical c-plane epilayers. The lower electron mobility is attributed to the higher density of structural defects in a-plane GaN.

Outline

  • Introduction
  • Experimental Details
  • Growth
  • Characterization
  • Results and Discussion
  • Conclusions
  • Acknowledgments

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    Cite this article as: MRS Internet J. Nitride Semicond. Res. 8, 6(2003).

    last updated Monday, September 8, 2003 3:05:36 PM.

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