1. Department of Materials Science and Engineering and Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Hsinchu 30013 Taiwan
2. Department of Physics National Sun Yat‐Sen University Kaohsiung 80424 Taiwan
3. Institute of Electronics Engineering and Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Hsinchu 30013 Taiwan
4. National Applied Research Laboratories Taiwan Semiconductor Research Institute Hsinchu Taiwan
5. Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan
6. Instrument Center National Tsing Hua University Hsinchu 30013 Taiwan