1. School
of Advanced Materials Engineering and Research Center of Advanced
Materials Development, Chonbuk National University, Jeonju 561-756, Korea
2. LED Device Research
Center, Korea Photonics Technology Institute, Gwangju 500-779, Korea
3. Institue of Rare Metals, B. Tolmachevsky, 5, Moscow, 119017, Russia
4. Device R&D Team, Seoul OptoDevice Co., Gyeonggi 425-851, Korea