1. School of Physics & Microelectronics, and Key Laboratory of Materials Physics of Ministry of Education of China, Zhengzhou University, Zhengzhou 450052, China
2. Henan Key Laboratory of Photovoltaic Materials and School of Future Technology (Quantum Information), Henan University, Kaifeng 475004, China
3. School of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou 466001, China