1. Department of Physics, Banaras Hindu University (BHU), Varanasi, India
2. Department of Electronics Engineering, IIT (BHU), Varanasi, Varanasi, India
3. School of Material Science and Technology, IIT (BHU), Varanasi, Varanasi, India
4. Department of Physics, Veer Bahadur Singh Purvanchal University, Jaunpur, India