GaN layers with different polarities prepared by radio frequency molecular beam epitaxy and characterized by Raman scattering
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)
Key Laboratory of Material Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
Abstract 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$^{ - 3}$.
Received: 11 December 2006
Revised: 15 February 2007
Accepted manuscript online:
PACS:
81.15.Hi
(Molecular, atomic, ion, and chemical beam epitaxy)
Fund: Project supported by the
National Natural Science Foundation of China (Grant No 10574130).
Cite this article:
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) GaN layers with different polarities prepared by radio frequency molecular beam epitaxy and characterized by Raman scattering 2007 Chinese Physics 16 2786
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