1. Centre for Advanced Devices and Systems, Faculty of Engineering, Multimedia University, Persiaran Multimedia, 63100 Cyberjaya, Selangor, Malaysia
2. Nanotechnology and Catalysis Research Centre (NANOCAT), Universiti Malaya, 50603, Kuala Lumpur, Malaysia
3. Electronic and Communications Department, College of Engineering, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia
4. Institute of Sustainable Energy, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia
5. International School of Advanced Materials, South China University of Technology, 381 Wushan Road, Tianhe District, Guangzhou, Guangdong, P. R. China