1. Department of Physics, National Sun Yat-sen University, 70 Lien-hai Road, Kaohsiung 80424, Taiwan
2. Advanced Optoelectronics Technology Center, National Cheng Kung University, No.1, University Road, Tainan 70101, Taiwan
3. Department of Electronics Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan
4. Department of Photonics, National Sun Yat-sen University, 70 Lien-hai Road, Kaohsiung 80424, Taiwan
5. Device Department, United Microelectronics Corporation, No.18, Nanke 2nd Rd., Tainan Science Park, Sinshih Dist., Tainan 74147, Taiwan