1. Department of Electrical Engineering, National Taiwan Ocean University, No.2 Pei-Ning Road, Keelung 20224, Taiwan
2. Photovoltaics Technology Center, Industrial Technology Research Institute, No.195 Chung Hsing Road, 4 Sec. Chu Tung, Hsin Chu 31061, Taiwan
3. Department of Microelectronic Engineering, National Kaohsiung Marine University, No.142 Haijhuan Road, Kaohsiung 81143, Taiwan
4. Device Research Laboratory, Department of Electrical Engineering, University of California, Los Angeles, CA 90095, USA