A comparative study of the cell performance of CIGS thin-film solar cells fabricated using ZnO:Al and ZnO:B window layers has been carried out. ZnO:B films were deposited by RF magnetron sputtering using an undoped ZnO target in a B2H6-Ar gas mixture. The shortcircuit current (J(sc)) was found to improve upon the replacement of the ZnO:Al layer with ZnO:B layers. This improvement in J(sc) is attributed to an increase in quantum efficiency due to the higher optical transmission of the ZnO:B layer in the near-infrared region. The best cell fabricated with a MgF2 /ZnO:B/i-ZnO/CdS/CIGS/Mo structure yielded an active area efficiency of 18.0% with V-oc = 0.645 V, J(sc) = 36.8 mA/cm(2), FF = 0.76, and an active area of 0.2cm(2) under AM 1.5 illumination. (C) 2001 Elsevier Science B.V. All rights reserved.