1. Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences 1219 Zhongguan West Rd Ningbo 315201, Zhejiang Province P. R. China
2. Nano Science and Technology Institute University of Science and Technology of China 166 Renai Rd Suzhou 215123, Jiangsu Province P. R. China
3. Physik-Department, Lehrstuhl für Funktionelle Materialien Technische Universität München James-Franck-Strasse 1 85748 Garching Germany
4. Innovation Academy for Green Manufacture Chinese Academy of Sciences Beijing 100190 P. R. China
5. Heinz Maier-Leibnitz Zentrum (MLZ) Technische Universität München Lichtenbergstr. 1 85748 Garching Germany
6. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences 19 A Yuquan Rd, Shijingshan District Beijing 100049 P. R. China