1. Department
of Electronic Engineering, Incheon National University, Incheon 406-772, Korea
2. Department
of Materials Science and Engineering and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
3. Department
of Electrical Engineering, Seoul National University, Seoul 151-600, Korea
4. Display R&D Center, Samsung Display Co., Yongin-city, Gyeongki-do 446–711, Korea
5. Center
for Neuroscience Imaging Research (CNIR), Institute of Basic Science
(IBS), School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, Gyeonggi-do 440-746, Korea
6. Department
of Materials Science and Engineering, Chemistry, Mechanical Science
and Engineering, Electrical and Computer Engineering, Beckman Institute
for Advanced Science and Technology, and Frederick Seitz Materials
Research Laboratory, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States