1. School of Physics & Electronics
2. Henan University
3. Kaifeng
4. People's Republic of China
5. Key Lab of Photovoltaic Materials of Henan Province
6. Department of Materials Science
7. School of Physical Science and Technology
8. Lanzhou University
9. Lanzhou 730000
10. Laboratory of Beijing Synchrotron Radiation
11. Institute of High Energy Physics
12. Chinese Academy of Sciences
13. Beijing 100049