1. Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
2. Department of Physics, National Central University, Jhongli 320, Taiwan
3. Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
4. Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei 106, Taiwan
5. Program on Key Materials, Academy of Innovative Semiconductor and Sustainable Manufacturing, National Cheng Kung University, Tainan 701, Taiwan
6. Nanoscience Group, National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
7. Institute of Electronic Engineering, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
8. International College of Semiconductor Technology, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
9. Department of Physics, National Changhua University of Education, Changhua 500, Taiwan