Institution: | a School of Advanced Materials and Nanotechnology, Xidian University, Xi’an 710071, China;b Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi’an 710071, China;c Key Laboratory of Microelectronics Device & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China |