Abstract This paper finds that the two-dimensional electron gas density in high Al-content AlGaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was investigated in depth using Hall effect measurements, high resolution x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy. The results reveal that the formation of surface oxide is the main reason for the degradation, and the surface oxidation always occurs within the surface hexagonal defects for high Al-content AlGaN/GaN heterostructures.
Received: 21 November 2008
Revised: 01 January 2009
Accepted manuscript online:
PACS:
73.63.-b
(Electronic transport in nanoscale materials and structures)
Fund: Project
supported by the Major Program and State Key Program of National
Natural Science of China (Grant Nos 60890191 and 60736033) and the
National Key Science {\&} Technology Special Project (Grant No
2008ZX 01002).
Cite this article:
Zhang Jin-Cheng(张进成), Zheng Peng-Tian(郑鹏天), Zhang Juan(张娟), Xu Zhi-Hao(许志豪), and Hao Yue(郝跃) Degradation mechanism of two-dimensional electron gas density in high Al-content AlGaN/GaN heterostructures 2009 Chin. Phys. B 18 2998
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