The performance of a GaAs p-n junction solar cell was investigated by coating the device with 110 nm thick ZnO sol-gel anti-reflection film. A post-furnace thermal annealing at 150 degrees C for 30 min was performed on the ZnO film after it was spin coated on the device with a speed of 8000 rpm. Ellipsometry was used to measure the reflectance, thickness, and the refractive index of the ZnO film. The solar cell performance was investigated by using the current-voltage technique from which the power conversion efficiency was extracted. The spectral response and quantum efficiency were also measured for the solar cell. An enhancement, after utilizing the ZnO anti-reflection coating, was observed on the order of 32%, 38, and 51% for the power conversion efficiency, spectral response, and quantum efficiency, respectively. (C) 2014 Elsevier B.V. All rights reserved.