1. National Key Laboratory of Wide Bandgap Semiconductor Devices and Integrated Technology and Shaanxi Joint Key Laboratory of Graphene, School of Microelectronics, Xidian University, 2 South Taibai Road, Xi’an 710071, China
2. Shaanxi Key Laboratory of High-Orbits-Electron Materials and Protection Technology for Aerospace, School of Advance Materials and Nanotechnology, Xidian University, 2 South Taibai Road, Xi’an 710071, China
3. Xi’an Baoxin Solar Technology Co., Ltd., Xi’an 710126, China