1. School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
2. Institute of Physics, University of Zielona Góra, ul. Prof. Z. Szafrana 4a, 65-516 Zielona Góra, Poland
3. Institute of Physics, Częstochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Częstochowa, Poland
4. Institute of Physics, Jan Długosz University in Częstochowa, Ave. Armii Krajowej 13/15, 42-200 Częstochowa, Poland
5. State Key Laboratory for Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China