Abstract This paper reports that cathodoluminescence (CL) measurements have been done to study the alloy fluctuation of the Al0.3Ga0.7N layer in Al0.3Ga0.7N/GaN heterostructures. The CL images and linescanning results demonstrate the existence of compositional fluctuation of Al in the Al0.3Ga0.7N barrier. A model using a $\delta$-shape perturbation Hamilton function has been proposed to simulate the scattering probability of the two dimensional electron gases (2DEG) induced by Al composition fluctuation. Two factors, including conduction band fluctuation and polarization electric field variation, induced by the Al composition fluctuation have been taken into account. The scattering relaxation time induced by both factors has been estimated to be 0.31 ns and 0.0078 ns, respectively, indicating that the variation of the piezoelectric field is dominant in the scattering of the 2DEG induced by Al fluctuation.
Received: 17 November 2008
Revised: 19 December 2008
Accepted manuscript online:
PACS:
73.40.Kp
(III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)
Fund: Project supported by the National
Natural Science Foundation of China (Grant Nos 10774001, 60736033
and 60628402), and National Basic Research Program of China (Grant
Nos 2006CB604908 and 2006CB921607).
Cite this article:
Wang Yan(王彦), Shen Bo(沈波), Xu Fu-Jun(许福军), Huang Sen(黄森), Miao Zhen-Lin(苗振林), Lin Fang(林芳), Yang Zhi-Jian(杨志坚), and Zhang Guo-Yi(张国义) Scattering behaviour of a two-dimensional electron gas induced by Al composition fluctuation in AlxGa1-x Nbarrier in AlxGa1-xN/GaN heterostructures 2009 Chin. Phys. B 18 2002
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