1. School of Information and Communications/Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), 123 Chemdangwagi-ro, Buk-gu, Gwangju, 500-712, South Korea
2. Solar City Center, Korea Institute of Industrial Technology (KITECH), 208 Chemdangwagi-ro, Buk-gu, Gwangju, 500-480, South Korea