1. Institute of Electronic Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
2. Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
3. Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan
4. Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
5. State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, Jilin 130012, PR China
6. Raynergy Tek Incorporation, Hsinchu Science Park, Hsinchu 30844, Taiwan
7. Taiwan Agricultural Research Institute, Wufeng, Taichung City 413008, Taiwan
8. Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
9. Institute of Nuclear Energy Research, Longtan, Taoyuan 32546, Taiwan