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. Colleage of Semiconductor Research National Tsing‐Hua University Hsinchu 30013 Taiwan
3. Department of Physics National Sun Yat‐Sen University Kaohsiung 80424 Taiwan
4. Institute of Electronics Engineering National Tsing Hua University Hsinchu 30013 Taiwan
5. Department of Materials Science and Engineering Korea University Seoul 02841 Republic of Korea