1. State Key Laboratory of Reliability and Intelligence of Electrical Equipment, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China
2. Hebei Engineering Laboratory of Photoelectronic Functional Crystals, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China
3. Department of Physics, Tianjin Chengjian University, Tianjin 300384, China