Evidence of two-dimensional hole gas in p-type AlGaN/AlN/GaN heterostructures

Qiyuan Wei, Zhihao Wu, Kewei Sun, Fernando Ponce, Joaquim Hertkorn, Ferdinand Scholz

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The electronic band structure of a modulation-doped p-type AlGaN/AlN/GaN heterostructure, where the AlGaN layer is compositionally graded, has been studied by electron holography. The electrostatic potential energy profile and the two-dimensional hole gas (2DHG) distribution have been measured with high spatial resolution across the heterostructure. A positive curvature in the potential profile has been observed, and it is considered as evidence for the accumulation of holes in a 2DHG at the AlN/GaN interface. It is also observed that the potential barrier for the 2DHG is greatly affected by acceptor ionization in the p-AlGaN layer. This knowledge of nature of the energy barriers for hole transfer between adjacent channels is important in the optimization of vertical conductivity of p-type AlGaN/GaN heterostructures, which can be used as current spreading layers in GaN-based light emitting diodes or laser diodes.

Original languageEnglish (US)
Article number121001
JournalApplied Physics Express
Volume2
Issue number12
DOIs
StatePublished - Dec 2009

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Heterojunctions
Gases
gases
Electron holography
Energy barriers
profiles
Potential energy
holography
Band structure
Ionization
Light emitting diodes
Semiconductor lasers
Electrostatics
light emitting diodes
spatial resolution
semiconductor lasers
potential energy
diodes
curvature
Modulation

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Evidence of two-dimensional hole gas in p-type AlGaN/AlN/GaN heterostructures. / Wei, Qiyuan; Wu, Zhihao; Sun, Kewei; Ponce, Fernando; Hertkorn, Joaquim; Scholz, Ferdinand.

In: Applied Physics Express, Vol. 2, No. 12, 121001, 12.2009.

Research output: Contribution to journalArticle

Wei, Qiyuan ; Wu, Zhihao ; Sun, Kewei ; Ponce, Fernando ; Hertkorn, Joaquim ; Scholz, Ferdinand. / Evidence of two-dimensional hole gas in p-type AlGaN/AlN/GaN heterostructures. In: Applied Physics Express. 2009 ; Vol. 2, No. 12.
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