1. Department of Electronic and Information Engineering, Research Institute for Smart Energy (RISE), The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, P. R. China
2. Thin-film Solar Technology Research Center, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, P. R. China
3. College of Physics and Electronic Information, Yunnan Normal University, Yunnan Kunming 650500, China
4. Yunnan Provincial Key Laboratory for Photoelectric Information Technology, Yunnan Normal University, Yunnan Kunming 650500, China
5. Department of Materials Science and Engineering, Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, P. R. China
6. Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, P. R. China