1. Department of Physics, Indian Institute of Technology Roorkee, Roorkee, Haridwar, Uttarakhand 247667, India
2. Institute for Photovoltaics (ipv), University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany
3. IEK5-Photovoltaics, Forschungszentrum Jülich, 52425 Jülich, Germany
4. Department of Solar Energy, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar, Gujarat 382 007, India
5. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States