State Key Laboratory of Integrated Optoelectronics;
Institute of Semiconductor;
Chinese Academy of Sciences;
Bejing 100083;
China;
College of Materials Science and Opto-Electronic Technology;
University of Chinese Academy of Sciences;
Beijing 100049;
China;
Centerof Materials Science and Optoelectronics Engineering;
University of Chinese Academy of Sciences;
Bejing 100049;
China;