CuInSe2 thin films have been obtained by the sequential evaporation of Cu and In layers, and subsequent reaction at 400degreesC with elemental selenium vapor. The individual metallic film thickness and the substrate temperature during evaporation have been varied in order to promote intermixing and alloy formation before the selenization. The structure, morphology and photoelectrochemical activity of the CuInSe2 films have been determined by the characteristics of the evaporated metallic precursors. An improvement in the CuInSe2 quantum efficiency, related mainly to the increased homogeneity and smoothing of the sample surface, can be gained by using as precursors multiple stacked Cu-In bilayers evaporated onto unheated substrates. (C) 2002 Elsevier Science B.V. All rights reserved.