1. Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea.
2. Department of Microdevice Engineering, Korea University, Seoul 02841, Korea.
3. Department of Semiconductor Science and Technology, Chonbuk National University, Jeonju 54896, Korea.
4. Department of Electronic Engineering, Gachon University, Seongnam 13306, Korea.
5. SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 16419, Korea.