1. School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
2. School of Chemical and Environmental Engineering, Liaoning University of Technology, Jinzhou, Liaoning 121001, China
3. Shanghai Huali Intergrated Circuit Corporation, No. 6 Liang Teng Road, Pudong
New District, Shanghai 201314, China
4. Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
5. Department of Applied Physics, KTH-Royal Institute of Technology, Hannes Alfvéns väg 12, 11419 Stockholm, Sweden