1. Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
2. Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
3. Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan
4. Frontier Research Center on Fundamental and Applied Science of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
5. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan