1. Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, 5340 Xiping Road, Tianjin 300401, People's Republic of China
2. School of Microelectronics, Tianjin University, 92 Weijin Road, Tianjin 300072, People's Republic of China
3. College of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, People's Republic of China