1. State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
2. University of Chinese Academy of Sciences, Beijing 100049, P. R. China
3. College of Physics and Information Engineering, Quanzhou Normal University, Quanzhou 362000, P. R. China
4. Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong 999077, P. R. China