1. Shenzhen Key Laboratory of Advanced Thin Films and Applications, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
2. Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, U.K.
3. China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
4. Key Laboratory of Micro and Nano Systems for Aerospace, Ministry of Education, Northwestern Polytechnical University, Xi’an 710072, P. R. China