1. School of Electronic Information and Artificial Intelligence, Shaanxi University of Science and Technology, Xi'an 710049, China
2. School of Electronics and Information Engineering, Nantong Vocational University, Nantong 226007, China
3. Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China