1. Collaborative Innovation Center for Nanomaterials & Devices
2. College of Physics
3. Qingdao University
4. Qingdao 266071
5. China
6. Department of Electronic & Computer Engineering
7. The Hong Kong University of Science & Technology
8. Kowloon
9. Center for Nanofibers & Nanotechnology
10. Nanoscience & Nanotechnology Initiative
11. Faculty of Engineering
12. National University of Singapore
13. Singapore