1. Korean Research Institute of Standards and Science (KRISS) 1 , 267 Gajeong-ro, Daejeon 34113, South Korea
2. Korean University of Science and Technology (UST) 2 , 217 Gajeong-ro, Daejeon 34113, South Korea
3. Institut für Physik, Humboldt-Universität zu Berlin 3 , Brook-Taylor-Strasse 6, Berlin 12489, Germany
4. Institute of Chemistry, Chinese Academy of Sciences (CAS) 4 , 2 North 1st Street, Zhongguancun, Beijing 100190, People's Republic of China
5. SK Hynix 5 , 2091 Gyeongchung-daero, Icheon-si, Gyeonggi-do 17336, South Korea
6. Department of Physics, Kyung Hee University 6 , 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, South Korea
7. Department of Information Display 7 , , Kyung Hee University, Seoul 02447, South Korea