1. Department of Physics, National Central University, Taoyuan 32001, Taiwan
2. Molecular Science and Technology Program, Taiwan International Graduate Program, Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
3. Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
4. Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
5. National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
6. Department of Physics, National Taiwan Normal University, Taipei 10610, Taiwan
7. Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan