Three-dimensional hole gas induced by polarization in „0001…-oriented

摘要

Polarization-doping via graded AlGaN layer on N-face u00020001 ¯u0003 GaN has been demonstrated as anninspiring p-type doping method for wide-band-gap nitrides. However, the polarity of III-nitridesngrown by metal organic chemical vapor deposition is metal-face typically. In this paper, we shownthat three-dimensional mobile hole gas induced by polarization can be formed in u00020001u0003-orientednmetal-face III-nitride structure. The hole concentration of a Mg-doped AlxGa1−xN layer with gradednAl composition from x=0.3 to 0 grown on AlN buffer layer is remarkably enhanced, compared withnthat of a Mg-doped GaN layer grown under the same conditions. In addition, the hole concentrationnin the graded AlGaN layer is absence of freezeout as the temperature decreases, indicating thatnthe hole is induced by polarization. This p-type doping method paves a way for achievingnhigh-efficiency in wide-band-gap semiconductor light-emitting devices with p-type doping problem.n© 2010 American Institute of Physics. u0004doi:10.1063/1.3478556