1. Key Laboratory of Optoelectronic Technology and System (Ministry of Education), College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China
2. The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
3. Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration, Wuhan University, Wuhan 430072, China
4. Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
5. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States