1. Division of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, P.O. Box 35, 75103 Uppsala, Sweden
2. Faculty of Electronics and Informational Technologies, Sumy State University, 2 Rymsky Korsakov Str., 40007 Sumy, Ukraine
3. Division of Solid State Electronics, Department of Electrical Engineering, Uppsala University, P.O.
Box 65, 75103 Uppsala, Sweden