[1] Tech Univ Carolo Wilhelmina Braunschweig, Inst Semicond Technol, D-38106 Braunschweig, Germany
[2] Univ Barcelona, Dept Elect, E-08028 Barcelona, Spain
[3] Tech Univ Carolo Wilhelmina Braunschweig, Lab Emerging Nanometrol, D-38106 Braunschweig, Germany
[4] Fraunhofer Inst Mech Mat IWM, D-79108 Freiburg, Germany
[5] Catalonia Inst Energy Res, Dept Adv Mat Energy Applicat, Barcelona 08930, Spain
[6] Tech Univ Clausthal, Inst Energy Res & Phys Technol, D-38678 Clausthal Zellerfeld, Germany