中国物理B ›› 2007, Vol. 16 ›› Issue (9): 2786-2790.doi: 10.1088/1009-1963/16/9/048
钟飞, 李新化, 邱凯, 尹志军, 姬长建, 曹先存, 韩奇峰, 陈家荣, 王玉琦
Zhong Fei(钟飞)†, Li Xin-Hua(李新化), Qiu Kai(邱凯), Yin Zhi-Jun(尹志军), Ji Chang-Jian(姬长建), Cao Xian-Cun(曹先存), Han Qi-Feng(韩奇峰), Chen Jia-Rong(陈家荣), and Wang Yu-Qi(王玉琦)
摘要: GaN layers with different polarities have been prepared by radio-frequency molecular beam epitaxy (RF-MBE) and characterized by Raman scattering. Polarity control are realized by controlling Al/N flux ratio during high temperature AlN buffer growth. The Raman results illustrate that the N-polarity GaN films have frequency shifts at $A_{1}$(LO) mode because of their high carrier density; the forbidden $A_{1}$(TO) mode occurs for mixed-polarity GaN films due to the destroyed translation symmetry by inversion domain boundaries (IDBS); Raman spectra for Ga-polarity GaN films show that they have neither frequency shifts mode nor forbidden mode. These results indicate that Ga-polarity GaN films have a better quality, and they are in good agreement with the results obtained from the room temperature Hall mobility. The best values of Ga-polarity GaN films are 1042 cm$^{2}$/Vs with a carrier density of 1.0$\times $10$^{17}$~cm$^{ - 3}$.
中图分类号: (Molecular, atomic, ion, and chemical beam epitaxy)