1. School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, People’s Republic of China
2. Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan, Hunan 411105, People’s Republic of China
3. Hunan Provincial Key Laboratory of Thin Film Materials and Devices, Xiangtan, Hunan 411105, People’s Republic of China