1. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai 200500, China
2. Department of Microelectronic Science and Engineering, Faculty of Science, Ningbo University, Ningbo 315211, China
3. Department of Materials Science, Fudan University, Shanghai 200433, China
4. Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801