1. School of Electronic Science and Applied Physics and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices; Hefei University of Technology; Hefei Anhui 230009 PR China
2. Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science; City University of Hong Kong; Hong Kong SAR PR China
3. School of Materials Science and Engineering; Hefei University of Technology; Hefei Anhui 230009 PR China