1. Hubei Key Laboratory of Plasma Chemistry and Advanced MaterialsWuhan Institute of Technology Wuhan 430205 People's Republic of China
2. Guangxi Key Laboratory of Information MaterialsGuilin University of Electronic Technology Guilin 541004 P.R. China
3. Zhongshan Branch of State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaZhongshan Institute Zhongshan 528402 P.R. China