1. Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 300044, Taiwan R. O. C.
2. Department of Electrical, Electronics and Information Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
3. Research Institute of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan
4. Department of Applied Chemistry, National Yang Ming Chiao Tung University, No. 1001, Daxue Rd. East Dist., Hsinchu 300093, Taiwan R. O. C.