1. Department of Physics, National Taiwan University, Taipei 10617, Taiwan
2. Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
3. Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
4. Center for Emerging Material and Advanced Device, National Taiwan University, Taipei 10617, Taiwan
5. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan