TY - JOUR
T1 - Evidence of two-dimensional hole gas in p-type AlGaN/AlN/GaN heterostructures
AU - Wei, Qiyuan
AU - Wu, Zhihao
AU - Sun, Kewei
AU - Ponce, Fernando
AU - Hertkorn, Joaquim
AU - Scholz, Ferdinand
PY - 2009/12/1
Y1 - 2009/12/1
N2 - 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.
AB - 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.
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U2 - 10.1143/APEX.2.121001
DO - 10.1143/APEX.2.121001
M3 - Article
AN - SCOPUS:73149090128
SN - 1882-0778
VL - 2
JO - Applied Physics Express
JF - Applied Physics Express
IS - 12
M1 - 121001
ER -