1. Department of Photonics and Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang-Ming Chiao Tung University, Hsinchu 30010, Taiwan
2. Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, Taiwan
3. International College of Semiconductor Technology, National Yang-Ming Chiao Tung University, Hsinchu 30010, Taiwan