1. Microelectronics and Nanotechnology-Shamsuddin Research Center, Institute for Integrated Engineering, University Tun Hussein Onn Malaysia, Batu Pahat, 86400 Parit Raja, Johor, Malaysia
2. Department of Physics, Sri Sai Ram Engineering College, Sai Leo Nagar, Sirukalathur, Kanchipuram, Tamil Nadu 600044, India
3. Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu 641046, India