1. Department of Physics R.O.C. Military Academy Kaohsiung 830 Taiwan
2. Department of Applied Science R.O.C. Naval Academy Kaohsiung 813 Taiwan
3. Center for Nanoscience and Nanotechnology National Sun Yat-Sen University Kaohsiung 804 Taiwan
4. Department of Electrical and Electronic Engineering Chung Cheng Institute of Technology National Defense University Taoyuan 335 Taiwan
5. Department of Materials and Optoelectronic Science National Sun Yat-Sen University Kaohsiung 804 Taiwan