1. Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan
2. College of Semiconductor Research, National Tsing Hua University, Hsinchu 30013, Taiwan
3. Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan
4. Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
5. Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
6. Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan
7. Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30013, Taiwan
8. Center for Applied Research in Electronics, Indian Institute of Technology Delhi, New Delhi 110016, India
9. European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38000, France
10. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
11. Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
12. National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan