We demonstrate an improvement in power conversion efficiency of single-junction GaAs solar cells incorporated with micro-hole arrays. The GaAs solar cells are grown by low-pressure metalorganic chemical vapor deposition on (100) GaAs substrates. The micro-hole arrays were formed on the surface of the GaAs solar cells, and the measurement on the reflectance and photocurrent generation are performed using an UV-Vis-NIR spectrometer and an external quantum efficiency measurement system, respectively. It is shown that the micro-hole arrays have the effect of scattering the incident light away from the original direction resulting in the reduction of reflectance over 350-873 nm spectrum regime. The micro-hole arrays formed on the surface of the solar cells enhanced the photocurrent generation which was increased with the extended optical path length in the absorption layer. As a result, an enhancement in power conversion efficiency of up to 12.3% compared to that of reference solar cell was obtained under 1 sun AM 1.5 G illumination at room temperature. (C) 2012 Elsevier B.V. All rights reserved.