1. Center for Excellence in Nanoscience Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS) National Center for Nanoscience and Technology Beijing 100190 China
2. University of Chinese Academy of Sciences Beijing 100049 China
3. Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of China Hefei 230026 China
4. School of Materials and Energy Yunnan University Kunming 650091 China
5. Department of Electrical Engineering Tsinghua University Beijing 100084 China
6. State Key Laboratory of Powder Metallurgy School of Physics and Electronics Central South University Changsha 410083 China
7. School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China