1. Department of Materials Science and Engineering National Tsing Hua University Hsinchu 30013 Taiwan
2. Department of Chemistry National Taiwan University Taipei 10617 Taiwan
3. Department of Photonics College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan
4. Department of Electrophysics College of Science National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan
5. Semiconductor Research Center Hon Hai Research Institute Taipei 11492 Taiwan
6. Institute of Atomic and Molecular Science Academia Sinica Taipei 10617 Taiwan
7. Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Hsinchu 30013 Taiwan