1. Songshan Lake Materials Laboratory, Dongguan 523808, P. R. China
2. Fujian Provincial Key Laboratory of Welding Quality Intelligent Evaluation, Longyan University, Longyan 364012, P. R. China
3. Department of Applied Physics, The Hong Kong Polytechnic University, Hunghom, Kowloon 999077, Hong Kong, P. R. China
4. School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, P. R. China
5. Institute of Physics, Chinese Academy of Science, Beijing 100190, P. R. China
6. Institute of Energy Materials Science (IEMS), University of Shanghai for Science and Technology, Shanghai 200093, P. R. China