1. Department of Electrical and Computer Engineering, Ajou University, Suwon 16499, South Korea.
2. Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA.
3. Department of System Semiconductor Engineering, Yonsei University, Seoul 03722, South Korea.
4. Department of Materials Science and Engineering, Yonsei University, Seoul 03722, South Korea.
5. School of Electronic Engineering, Soongsil University, Seoul 06938, South Korea.
6. Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea.
7. Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea.
8. Department of Material Science and Engineering, University of Virginia, Charlottesville, VA 22904, USA.