1. Center for Opto‐Electronic Materials and Devices Post‐Silicon Semiconductor Institute Korea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
2. Division of Nano & Information Technology KIST School University of Science and Technology (UST) Seoul 02792 Republic of Korea
3. SKKU Advanced Institute of Nano Technology (SAINT) Sungkyunkwan University (SKKU) Suwon 16419 Korea
4. Advanced Analysis Center Korea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
5. Advanced Materials Laboratory National Institute for Materials Science Tsukuba 305‐0044 Japan
6. Department of Physics Kunsan National University Gunsan 54150 Republic of Korea