Variation of band bending at the surface of Mg-doped InGaN:: Evidence of p-type conductivity across the composition range

被引:57
作者
King, P. D. C.
Veal, T. D.
Jefferson, P. H.
McConville, C. F. [1 ]
Lu, Hai
Schaff, W. J.
机构
[1] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England
[2] Cornell Univ, Dept Elect & Comp Engn, Ithaca, NY 14853 USA
来源
PHYSICAL REVIEW B | 2007年 / 75卷 / 11期
基金
英国工程与自然科学研究理事会;
关键词
D O I
10.1103/PhysRevB.75.115312
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The variation of band bending as a function of composition at oxidized (0001) surfaces of Mg-doped In(x)Ga(1-x)N is investigated using x-ray photoelectron spectroscopy. Distinctly different trends in barrier height are seen for the Mg-doped compared to undoped alloys, which is explained in terms of Fermi-level pinning at the surface and virtual gap states. Solutions of Poisson's equation within the modified Thomas-Fermi approximation are used to model the band bending and corresponding variation of carrier concentration with depth below the surface. A transition from a surface inversion layer for In-rich alloys to a surface hole depletion layer for Ga-rich alloys occurs at x approximate to 0.49. The trend in barrier height, calculated space-charge profiles, and difference of barrier height for undoped and Mg-doped InN indicate that Mg doping induces bulk p-type conductivity across the entire composition range.
引用
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页数:7
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