1. Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan 30013, R. O. C.
2. School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
3. Research Center for Applied Sciences, Academia Sinica, 128 Section 2, Academia Road, Nankang, Taipei City 11529, Taiwan
4. Electronic and Information Engineering, Hong Kong Polytechnic University, Hunghom, Kowloon 999077, Hong Kong