1. Department of Applied Physics, Delhi Technological University (Formerly Delhi College of Engineering), Bawana Road, Delhi 110042, India
2. Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
3. Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
4. Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
5. Department of Material Science and Engineering, University of North Texas, Denton, Texas 76203, United States
6. Department of Physics, Jamia Millia Islamia, New Delhi 110025, India
7. Microelectronics and Materials Physics Laboratories, Department of Electrical Engineering, University of Oulu, P.O. Box 4500, FI-90014 Oulu, Finland