1. Center for Nano Manufacturing, Inje University, Gimhae 621-749, Korea
2. Lighting Module Research and Development, Samsung Electro-Mechanics Co., Ltd., Suwon 443-373, Korea
3. Division of Advanced Materials Engineering, Chonbuk National University, Jeonju 561-756, Korea
4. Department of Physics, Yeungnam University, Gyeongsan 712-749, Korea
5. Division of General Education, Uiduk University, Gyeongju 780-713, Korea