1. Department
of Physics, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
2. ANA Artwork Material Analysis Ltd, Mong Kok, Hong Kong, China
3. The
Institute of Light and Matter, Université Claude Bernard Lyon 1 and the CNRS (UMR5306), 69622 Villeurbanne CEDEX, France
4. Thermo Scientific, Niton Analyzer Asia, Shatin, Hong Kong, China
5. Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
6. Institute
of Applied Physics and Materials Engineering, Faculty of Science and
Technology, University of Macau, Macau, China