1. Department of Electrical and Electronics Engineering Birla Institute of Technology and Science Pilani Hyderabad Campus Hyderabad 500078 India
2. Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autónoma de México A.P. 1–1010 Querétaro 76000 México
3. Materials Center for Sustainable Energy and Environment Birla Institute of Technology and Science Pilani Hyderabad Campus Hyderabad 500078 India