1. School of Electronic Science and Engineering, and State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of China Chengdu 610054 P. R. China
2. College of Materials Science and EngineeringSichuan University Chengdu 610065 P. R. China
3. Interdisciplinary Nanoscience Center (iNANO)Aarhus University DK‐8000 Aarhus C Denmark