1. Department of Physics B. S. Abdur Rahman University Chennai Tamil Nadu 600048 India
2. Department of Physics Velammal College of Engineering & Technology Viraganoor Madurai Tamil Nadu 625009 India
3. NANO‐Electronic Centre, Faculty of Electrical Engineering Universiti Teknologi MARA Shah Alam Selangor 40450 Malaysia
4. UGC‐DAE Consortium for Scientific Research, Kalpakkam Node, Kokilamedu Kalpakkam Tamil Nadu 603104 India