1. Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung, Taiwan
2. Department of Applied Science, ROC Naval Academy, Kaohsiung, Taiwan
3. Center of Crystal Research and the Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
4. Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
5. Department of Electronics Engineering, National Tsing Hua University, Hsinchu, Taiwan
6. Department of Electronics Engineering, National Chiao Tung University, Hsinchu, Taiwan
7. Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan