1. Photonics Energy Research Division Korea Photonics Technology Institute Gwangju 61007 Republic of Korea
2. Photonic Semiconductor & Display Research Division Korea Photonics Technology Institute Gwangju 61007 Republic of Korea
3. Research Center for Nitride Single Crystals LumiGNtech Co., Ltd. Gyeonggi 14322 Republic of Korea
4. Department of Photonic Engineering Chosun University Gwangju 61452 Republic of Korea
5. Department of Materials Science and Engineering Chungnam National University Daejeon 34134 Republic of Korea