1. Xinjiang Key Laboratory of Solid State Physics and Devices, Xinjiang University, Urumqi 830046, Xinjiang, People′s Republic of China
2. School of Physics Science and Technology, Xinjiang University, Urumqi 830046, Xinjiang, People′s Republic of China
3. Department of Physics, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Xiamen University, Xiamen 361005, People′s Republic of China