This work presents an overview of recent results obtained in the field of III-V solar cell research as performed at the Radboud University Nijmegen. An n-type AlxGa1-xInP2 Window layer with x = 1 was found to give the highest GaAs cell performance, in spite of a low doping carrier concentration as compared to GaInP2. As a result of the optimization of the GaAs cell structure obtained by metalorganic chemical vapor deposition (MOCVD) and subsequent processing, thin-film cells transferred from their native GaAs substrate to a foreign carrier, were achieved with a conversion efficiency of 24.5%. This is a world record for single-junction thin-film cells. Difficulties in the processing of thin-film GaInP2 cells, due to anomalous etching behavior of these layers in HCl, have been overcome by using a HBr/Br-2/H2O mixture as an etchant. Thin-film GaInP2 cells with efficiencies up to 11.4% were obtained. (c) 2006 Elsevier B.V. All rights reserved.