1. Walter Schottky Institute and Physics Department
2. Technische Universität München
3. 85748 Garching
4. Germany
5. Energy Technologies Area
6. Lawrence Berkeley National Laboratory
7. Berkeley
8. USA
9. Department of Materials Science and Engineering
10. Institute of Fundamental and Frontier Sciences
11. University of Electronic Science and Technology of China
12. Chengdu 610054
13. P. R. China