1. Department of Microelectronics Science and Engineering, School of Physical Science and Technology, Ningbo University, Ningbo 315211, People’s Republic of China
2. Department of Foundation, Ningbo City College of Vocational & Technology, Ningbo 315100, People’s Republic of China
3. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People’s Republic of China