1. Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education& Hunan Provincial Key Laboratory of Low‐Dimensional Structural Physics and Devices School of Physics and Electronics Hunan University Changsha 410082 China
2. State Key Laboratory of ASIC and System Department of Microelectronics Fudan University Shanghai 200433 P. R. China
3. College of Semiconductors (College of Integrated Circuits) Hunan University Changsha 410082 China