The Spray Ion Layer Gas Reaction (Spray-ILGAR) technique is a new variation on the ILGAR technique used to prepare chalcogenide thin films. High quality indium sulfide thin films were produced by Spray-ILGAR with an indirect bandgap of 2.2 eV and a high suitability for use as buffer layers in chalcopyrite solar cells. The process involves the cyclical spray deposition of an indium containing precursor layer followed by its conversion to sulfide using hydrogen sulfide gas. Analysis of the deposition reveals that the indium chloride based precursor is transported via the vapour phase from the spray droplets to the substrate surface. (c) 2006 Elsevier B.V. All rights reserved.