1. School of Microelectronics, South China University of Technology, 510641 Guangzhou, China
2. Department of Physics, University of Gothenburg, 41296 Gothenburg, Sweden
3. School of Microelectronics, Northwestern Polytechnical University, 710072 Xi’an, China
4. Yangtze River Delta Research Institute of NPU, Taicang, 215400 Jiangsu, China
5. Department of Physics Education, Korea National University of Education, 28173 Cheongju, Korea
6. School of Engineering Sciences, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
7. NanOsc AB, 16440 Kista, Sweden