Affiliation: | 1. Faculty of Physics and Electronic Technology and Nanotechnology Research Centre, Hubei University, Wuhan 430062, PR China;2. Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong;3. Department of Physics, The Chinese University of Hong Kong, Hong Kong;4. Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China |