Quantum dots-templated growth of strain-relaxed GaN on a c-plane sapphire by radio-frequency molecular beam epitaxy

We investigated the quantum dots-templated growth of a（0001） GaN film on a c-plane sapphire substrate.The growth was carried out in a radio-frequency molecular beam epitaxy system.The enlargement and coalescence of grains on the GaN quantum dots template was observed in the atom force microscopy ima...

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Published inChinese physics B Vol. 21; no. 10; pp. 485 - 490
Main Author 郭浩民 文龙 赵志飞 步绍姜 李新化 王玉琦
Format Journal Article
LanguageEnglish
Published 01.10.2012
Subjects
Density
Electron gas
Enlargement
Gallium nitrides
GaN
Molecular beam epitaxy
Quantum dots
Raman spectra
Sapphire
分子束外延生长
平面
应变弛豫
模板化
电子迁移率
蓝宝石衬底
量子点
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ISSN1674-1056
2058-3834
1741-4199
DOI10.1088/1674-1056/21/10/108101

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Summary:We investigated the quantum dots-templated growth of a（0001） GaN film on a c-plane sapphire substrate.The growth was carried out in a radio-frequency molecular beam epitaxy system.The enlargement and coalescence of grains on the GaN quantum dots template was observed in the atom force microscopy images,as well as the more ideal surface morphology of the GaN epitaxial film on the quantum dots template compared with the one on the AlN buffer.The Ga polarity was confirmed by the reflected high energy electron diffraction patterns and the Raman spectra.The significant strain relaxation in the quantum dots-templated GaN film was calculated based on the Raman spectra and the X-ray rocking curves.Meanwhile,the threading dislocation density in the quantum dots-templated film was estimated to be 7.1×107cm-2,which was significantly suppressed compared with that of the AlN-buffered GaN film.The roomtemperature Hall measurement showed an electron mobility of up to 1860cm2 /V·s in the two-dimensional electron gas at the interface of the Al 0.25Ga0.75 N/GaN heterojunction.
Bibliography:Guo Hao-Min,Wen Long,Zhao Zhi-Fei,Bu Shao-Jiang,Li Xin-Hua,and Wang Yu-Qi （Key Laboratory of Materials Physics,Institute of Solid State Physics,Chinese Academy of Sciences,Hefei 230031,China）
V semiconductor; radio-frequency molecular beam epitaxy; dislocation
11-5639/O4
We investigated the quantum dots-templated growth of a（0001） GaN film on a c-plane sapphire substrate.The growth was carried out in a radio-frequency molecular beam epitaxy system.The enlargement and coalescence of grains on the GaN quantum dots template was observed in the atom force microscopy images,as well as the more ideal surface morphology of the GaN epitaxial film on the quantum dots template compared with the one on the AlN buffer.The Ga polarity was confirmed by the reflected high energy electron diffraction patterns and the Raman spectra.The significant strain relaxation in the quantum dots-templated GaN film was calculated based on the Raman spectra and the X-ray rocking curves.Meanwhile,the threading dislocation density in the quantum dots-templated film was estimated to be 7.1×107cm-2,which was significantly suppressed compared with that of the AlN-buffered GaN film.The roomtemperature Hall measurement showed an electron mobility of up to 1860cm2 /V·s in the two-dimensional electron gas at the interface of the Al 0.25Ga0.75 N/GaN heterojunction.
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ISSN:1674-1056
2058-3834
1741-4199
DOI:10.1088/1674-1056/21/10/108101