1. Advanced Nanoelectronic Device & Circuit Research Group, Department of Electronics System Engineering, Indian Institute of Science, Bangalore, India;
2. Department of Electronics, Sri Venkateswara College, University of Delhi, New Delhi, India;
3. Department of Electronics, Deen Dayal Upadhyaya College, University of Delhi, New Delhi, India;
4. Semiconductor Device Research Laboratory, Department of Electronic Science, University of Delhi South Campus, New Delhi, India