1. Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
2. Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
3. Department of Physics, National Taiwan University, Taipei 10617, Taiwan
4. Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
5. Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan