1. Department of Materials Science and Engineering, Seoul National University, Seoul 08826, South Korea
2. Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, South Korea
3. Advanced Development Team, LED Business, Samsung Electronics, Yongin 17113, South Korea
4. Energy Semiconductor Research Center, Advanced Institutes of Convergence Technology, Seoul National University, Suwon 16229, South Korea
5. Research Institute of Advanced Materials and Inter-university Semiconductor Research Center, Seoul National University, Seoul 08826, South Korea