1. Key Laboratory of Low-Dimensional Materials and Application Technologies(Ministry of Education)Faculty of Materials Science and Engineering, Xiangtan University, Hunan 411105, China
2. Hunan Provincial Key Laboratory of Thin Film Materials and Devices, Faculty of Materials Science and Engineering, Xiangtan University, Hunan 411105, China
3. NOVITAS, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore