1. Key Laboratory of Luminescence and Optical Information; Ministry of Education; School of Science; Beijing Jiaotong University; Beijing 100044 P. R. China
2. International Center for Materials Nanoarchitectonics (MANA); National Institute for Materials Science (NIMS); Namiki 1-1 Tsukuba Ibaraki 3050044 Japan
3. Research Institute of Unconventional Petroleum and Renewable Energy; China University of Petroleum (East China); Qingdao 266580 P. R. China
4. School of Materials Science and Engineering; Hebei University of Technology; Tianjin 300130 P. R. China
5. Hebei Key Laboratory of Boron Nitride Micro- and Nano-Materials; Tianjin 300130 P. R. China