1. Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
2. Material and Chemical Research Laboratories, Nanotechnology Research Center, Industrial Technology Research Institute, Hsinchu 31040, Taiwan
3. Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu City 30013, Taiwan
4. Center for the Intelligent Semiconductor Nano-system Technology Research, National Chiao Tung University, Hsinchu 30010, Taiwan