1 State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
2 School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
3 Department of Physics and Astronomy, The University of Kansas, Lawrence, Kansas 66045, USA
4 Laboratory of Micro-Nano Optoelectronic Materials and Devices, Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
5 e-mail: qiannan@seu.edu.cn
6 e-mail: xcxseu@seu.edu.cn