Improved Jsc in CIGS thin film solar cells using a transparent conducting ZnO:B window layer

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 short-circuit current (Jsc) was found to improve upon the replacement of the ZnO:Al layer with ZnO:B layers. This improvement in Jsc 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 Voc=0.645 V, Jsc=36.8 mA/cm2, FF=0.76, and an active area of 0.2 cm2 under AM 1.5 illumination.