1. School of Mechanical and Electrical Engineering, Hunan Applied Technology University, Changde 415000, People's Republic of China
2. School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan, Hunan 411201, People's Republic of China
3. School of Microelectronics and Physics, Hunan University of Technology and Business, Changsha, 410205, People's Republic of China