1. Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong SAR 000000, P. R. China
2. Department of Chemistry, City University of Hong Kong, Kowloon 000000, Hong Kong SAR, P. R. China
3. Department of Material Science and Engineering, City University of Hong Kong, Kowloon 000000, Hong Kong SAR, P. R. China
4. Institute of Advanced Materials (IAM), Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, P. R. China