1. School of Electronic Engineering and the Department of Intelligent Semiconductors, Soongsil University, Seoul, South Korea
2. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
3. Department of Electrical and Computer Engineering and the Inter-University Semiconductor Research Center, Seoul National University, Seoul, South Korea
4. Department of Electrical and Computer Engineering, College of Information and Communication Engineering, Sungkyunkwan University, Suwon, South Korea