In this study, we fabricated a three-dimensional CuInS2 solar-cell structure using supercritical fluid deposition and sulfurization, in which p-n junction is formed at the large surface of a nanoporous n-type TiO2 film filled with a p-type CuInS2 semiconductor to facilitate the efficient collection of photoinduced electrons and holes. Using the reductive reaction of organometallic precursors dissolved in supercritical fluid at the surface, we successfully and efficiently deposited Cu-In film inside the nanoporous film consisting of TiO2 nanoparticles with a diameter of a few tens of nanometers. The CuInS2 film formed following the sulfurization of the Cu-In film exhibited an ideal band gap (1.5 eV) and photoconductivity. The results obtained in this study expand the applicability of supercritical fluid technology to the fabrication of chalcogenide semiconductors inside nanostructured materials and will contribute to the future development of or improvement in various types of energy devices. (C) 2016 Elsevier B.V. All rights reserved.