[1] Multidisciplinary Physics Research and Services Laboratory, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur,50603, Malaysia
[2] Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur,50603, Malaysia
[3] Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur,50603, Malaysia
[4] Centre for Ionics, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur,50603, Malaysia