Influence of potential fluctuations on electrical transport and optical properties in modulation-doped GaN/Al0.28Ga0.72N heterostructures

被引:17
作者
Buyanov, AV [1 ]
Bergman, JP
Sandberg, JA
Sernelius, BE
Holtz, PO
Monemar, B
Amano, H
Akasaki, I
机构
[1] Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden
[2] Meijo Univ, Dept Elect & Elect Engn, Tempaku Ku, Nagoya, Aichi 468, Japan
来源
PHYSICAL REVIEW B | 1998年 / 58卷 / 03期
关键词
D O I
10.1103/PhysRevB.58.1442
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We report transport and optical data for GaN/Al0.28Ga0.72N modulation-doped heterostructures grown by metal-organic chemical-vapor deposition. Variable temperature galvanomagnetic, resistivity, photoluminescence, and photoconductivity measurements have been performed. Evidence for potential fluctuations is provided by the observation of weakly localized transport at low temperatures, together with a negative magnetoresistance due to disorder in the interface region. The deduced localization criteria based on the theoretical modeling from Hall, resistivity and negative ma,magnetoresistance data are in a reasonable agreement with weak-localization conditions. Additional evidence for a built-in electric field caused by the fluctuations near the heterointerface region is given by the observation of photoconductivity dips resonant with free excitons, indicating free-exciton ionization. A theoretical modeling of the transport properties under various limiting scattering conditions is provided, and compared with the experimental data for the transport time and elastic lifetime. The potential fluctuations in the two-dimensional plane from the impurity distribution only are also modeled, and the results are consistent with the experimental indications for strong potential fluctuations. It is concluded that interface roughness, dislocations, and similar structural defects have a strong influence on the transport properties of the two-dimensional electron gas in these structures. [S0163-1829(98)06224-9].
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收藏
页码:1442 / 1450
页数:9
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