1. Department of Physics University of South Florida Tampa, Florida 33620 USA
2. Faculty of Materials Science and Engineering Phenikaa University Yen Nghia Ha Dong Hanoi 12116 Vietnam
3. Phenikaa Research and Technology Institute (PRATI) A&A Green Phoenix Group 167 Hoang Ngan Hanoi 13313 Vietnam
4. Department of Physics and Energy Harvest-Storage Research Center University of Ulsan Ulsan 680-749 Republic of Korea