1. Shenzhen Key Laboratory of Laser Engineering; College of Optoelectronic Engineering; Shenzhen University; Shenzhen 518060 P. R. China
2. Department of Physics; University of Antwerp; Antwerp BE-2020 Belgium
3. Department of Energy Materials and Technology; General Research Institute for Nonferrous Metals; Beijing 100088 P. R. China
4. State Key Laboratory of Silicon Materials; Department of Materials Science and Engineering; Zhejiang University; Hangzhou 310027 P. R. China
5. College of Electronic Science and Technology; Shenzhen University; Shenzhen 518060 P. R. China
6. School of Biomedical Engineering; Shanghai Jiao Tong University; Shanghai 200030 P. R. China