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Polarization-Induced Charges in Modulation-Doped AlxGa1-xN/GaN Heterostructures Through Capacitance-Voltage Profiling |
ZHOU Yu-Gang1;SHEN Bo1;YU Hui-Qiang1;LIU Jie1;ZHOU Hui-Mei1;ZHANG Rong1;SHI Yi1;ZHENG You-Dou1;T. Someya2;Y. Arakawa2 |
1National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093
2Research Center for Advanced Science and Technology and Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153, Japan |
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Cite this article: |
ZHOU Yu-Gang, SHEN Bo, YU Hui-Qiang et al 2002 Chin. Phys. Lett. 19 1172-1175 |
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Abstract Polarization-induced charges in modulation-doped Al0.22Ga0.78N/GaN heterostructures were investigated by the capacitance-voltage (C--V) method. The C--V profile of the Pt/Al0.22Ga0.78N/GaN Schottky diodes with various Al0.22Ga0.78N thickness shows significant differences due to change of the polarization field in the heterostructures. Numerical simulation based on the experimental results indicates that the sheet density of the polarization-induced charges at the heterointerface is 6.78 x 1012cm-2 in the samples with the Al0.22Ga0.78N thickness of 30 nm or 45 nm. The charge density reduces to 1.30 x 1012cm-2 in the sample with the Al0.22Ga0.78N thickness of 75 nm. It is thought that the reduction of the polarization-induced charges at the heterointerface is due to the partial relaxation of the Al0.22Ga0.78N layer on GaN. This work provides a technique for quantitative characterization of the polarization-induced charges in AlxGa1-xN/GaN heterostructures.
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Keywords:
73.40.Kp
73.40.Ei
73.61.Eg
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Published: 01 August 2002
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PACS: |
73.40.Kp
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(III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)
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73.40.Ei
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(Rectification)
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73.61.Eg
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