We calculated photoconversion efficiency in textured solar cells based on thin-film AlxGa1-xAs-GaAs heterostructure using the ray optics approximation. Most calculations were performed for the case when regular microrelief was a set of V-like grooves with base angle of 45degrees. Taking into account antireflection properties of SiO2 film deposited onto AlxGa1-xAs film, as well as of AlxGa1-xAs film itself, it was shown, in particular, that the reflection coefficient averaged over the solar radiation spectrum in the GaAs absorption region was below 1%. When calculating short-circuit current, we took into account both reflection coefficient decrease and growth of photon free path in p-GaAs layer. Aiming at provision of the highest photoconversion efficiency, we obtained the conditions for optimisation of grid area and doping levels in p- and n-GaAS layers. (C) 2003 Elsevier B.V. All rights reserved.