1. Department of Electrical and Electronic Engineering, Universiti Teknologi Petronas, Seri Iskandar 32610, Malaysia
2. Centre of Innovative Nanostructure and Nanodevices (COINN), Universiti Teknologi Petronas, Seri Iskandar 32610, Malaysia
3. Centre of Advanced Materials, Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur 50603, Malaysia