1. Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education & Key Disciplines Laboratory of Novel Micro-Nano Devices and System Technology, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China
2. International R & D center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing 400044, China