Influence of dislocations in the GaN layer on the electrical properties of an AlGaN/GaN heterostructure
Gao Zhi-Yuan(高志远),Hao Yue(郝跃)†, Zhang Jin-Cheng(张进城), Li Pei-Xian(李培咸), and Gu Wen-Ping(谷文萍)
Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China
Abstract This paper reports on a comparative study of the spatial distributions of the electrical, optical, and structural properties in an AlGaN/GaN heterostructure. Edge dislocation density in the GaN template layer is shown to decrease in the regions of the wafer where the heterostructure sheet resistance increases and the GaN photoluminescence band-edge energy peak shifts to a high wavelength. This phenomenon is found to be attributed to the local compressive strain surrounding edge dislocation, which will generate a local piezoelectric polarization field in the GaN layer in the opposite direction to the piezoelectric polarization field in the AlGaN layer and thus help to increase the two-dimensional electron gas concentration.
Received: 13 August 2008
Revised: 25 March 2009
Accepted manuscript online:
PACS:
73.40.Kp
(III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)
Fund: Project supported by the National
Key Basic Research and Development Program (973 Program) of China
(Grant Nos 2002CB3119 and 513270407).
Cite this article:
Gao Zhi-Yuan(高志远),Hao Yue(郝跃), Zhang Jin-Cheng(张进城), Li Pei-Xian(李培咸), and Gu Wen-Ping(谷文萍) Influence of dislocations in the GaN layer on the electrical properties of an AlGaN/GaN heterostructure 2009 Chin. Phys. B 18 4970
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