1. School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China
2. Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Sino-Singapore Guangzhou Knowledge City, Huangpu District, Guangzhou 510555, China
3. School of Materials Science and Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China
4. Key Lab of Si-based Information Materials & Devices and Integrated Circuits Design, Department of Education of Guangdong Province, Guangzhou 510006, China