1. Department of Materials Engineering and Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, New Taipei 243, Taiwan
2. Department of Electronic Engineering and Institute of Electro-Optical Engineering, Chang Gung University, Taoyuan 333, Taiwan
3. Department of Electronic Engineering, Ming Chuan University, Taoyuan 333, Taiwan
4. Department of Electronic Engineering, Feng Chia University, Taichung 407, Taiwan