1. Institute of Engineering Mathematics, University Malaysia Perlis, Taman Bukit Kubu Jaya, Jalan Serawak, Kuala Perlis, Perlis, 02000, Malaysia
2. Department of Physics, University of Illinois at Chicago, Chicago, Illinois, USA
3. School of Microelectronic Engineering, University Malaysia Perlis, Complex UniMAP, Jejawi, Perlis, 02600, Malaysia