1. School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
2. Institut für Solarenergieforschung Hameln/Emmerthal, Am Ohrberg 1, 31860 Emmerthal, Germany
3. SunEdison Semiconductor, Viale Gherzi 31, 28100 Novara, Italy
4. SunEdison Semiconductor, Via Nazionale 59, 39012 Merano, Italy