1. Department of Physics; Hong Kong Baptist University (HKBU); Kowloon Tong, Kowloon Hong Kong SAR China
2. Department of Physics; The Chinese University of Hong Kong; Shatin Hong Kong SAR China
3. Institute of Advanced Materials; Partner State Key Laboratory of Environmental and Biological Analysis; HKBU; Kowloon Tong, Kowloon Hong Kong SAR China
4. HKBU Institute of Research and Continuing Education; 9F, the Industrialization Complex of Shenzhen Virtual University Park; No. 2 Yuexing 3rd Road, South Zone, Hi-Tech Industrial Park Nanshan District Shenzhen 518057 Guangdong Province China