1. Institute of Physics, Vietnam Academy of Science and Technology, Ba Dinh, Ha Noi, Vietnam;
2. Physics Department, Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Cau Giay, Ha Noi, Vietnam;
3. Institute for Environmental and Transport Studies, Ho Chi Minh City University of Transport, Ho Chi Minh City, Vietnam;
4. Department of Materials Science and Engineering, University of Florida, Gainesville, FL, USA;
5. School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, Vietnam