1. SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon Gyeonggi-do 16419, Republic of Korea
2. Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, 100044 Beijing, P. R. China
3. LG Display, Paju-si, Gyeonggi-do 10845, Korea
4. Department of Nano Engineering, Sungkyunkwan University (SKKU), Suwon Gyeonggi-do 16419, Republic of Korea
5. Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea