1. College of Optoelectronic Engineering; Shenzhen University; Shenzhen 518060 P. R. China
2. Shenzhen Key Laboratory of Laser Engineering; College of Optoelectronic Engineering; Shenzhen University; Shenzhen 518060 P. R. China
3. Beijing Institute of Nanoenergy and Nanosystems; Chinese Academy of Sciences; Beijing 100083 P. R. China
4. Institute for Advanced Study; Shenzhen University; Shenzhen 518060 P. R. China