XIE Haiqing1, ZENG Chengwei1, ZENG Jianping2, TANG Junlong1,JIA Xinliang1, PENG Yongda1, WANG Chao1
(1. School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha 410114,China; 2. College of Physics and Microelectronics Science, Hunan University, Changsha 410082,China)