1. Institute of Materials Science, Vietnam Academy of Science and Technology, Hanoi, Vietnam
2. Institute of Physic and Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
3. Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
4. Faculty of Materials Science and Technology, University of Science, Ho Chi Minh City, Vietnam
5. Vietnam National University, Ho Chi Minh City, Vietnam
6. Department of Physics, Pusan National University, Busan 46241, Republic of Korea
7. Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea