1. School of Physics and Electronic-Electrical Engineering, Xiangnan University, Chenzhou 423000, China
2. State Key Laboratory for Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
3. Changsha Environmental Protection College, Hunan Province, Changsha 410082, China
4. Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha, China