1. Information Materials and Intelligent Sensing Laboratory of Anhui Province, Industry-Education-Research Institute of Advanced Materials and Technology for Integrated Circuits, School of Electronic and Information Engineering, Anhui University, Hefei, Anhui 230601, People’s Republic of China
2. Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072, People’s Republic of China