1. School of Semiconductor Science and Technology, South China Normal University, Foshan 528225, China
2. School of Electronic Engineering, Chaohu University, Hefei 238000, China
3. School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
4. School of Physical Science, University of Science and Technology of China, Hefei 230029, China
5. Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou 510631, China