Department of Physics, Nanchang University, Nanchang 330031;
Department of Physics, Nanchang University, Nanchang 330031;
Department of Physics, Nanchang University, Nanchang 330031;
Department of Physics, Nanchang University, Nanchang 330031;
Department of Physics, Nanchang University, Nanchang 330031;
The State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors,Chinese Academy of Sciences, Beijing 100083;