1. LAPS—Laboratory for Photovoltaics and Solid State Physics, Department of Computer ScienceUniversity of Verona Ca' Vignal 1, Strada Le Grazie 15 37134 Verona Italy
2. Stephenson Institute for Renewable Energy and Department of PhysicsUniversity of Liverpool Liverpool L69 7ZF UK
3. Department of Physics and Astronomy “G. Galilei”University of Padova Via F. Marzolo 8 35131 Padova Italy
4. Department of Materials Science and EngineeringUniversity of Michigan Ann Arbor MI USA