1. NUS Graduate School – Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077, Singapore
2. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
3. Anderson Serangoon Junior College, 4500 Ang Mo Kio Ave 6, Singapore 569843, Singapore
4. Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
5. Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore