Atomic Layer Deposition (ALD) of copper sulfide (CuxS) thin films from Cu(acac)(2) (acac = acetylacetonate = 2,4-pentanedionate) and H2S as Cu and S precursors is reported. Typical self-saturated reactions ("ALD window") are obtained in the temperature range T-dep = 130-200 degrees C for an average growth per cycle (GR) = 0.25 angstrom/cycle. The morphology, crystallographic structure, chemical composition, electrical properties and optical band gap of thin films were investigated using scanning electronic microscopy (SEM), X-ray diffraction under Grazing Incidence conditions (GI-XRD), X-ray reflectivity (XRR), energy dispersive spectrometry (EDS), Hall effect measurements, and UV-vis spectroscopy. The obtained copper sulfide films are heavily p-doped (charge carrier concentration similar to 10(21)-10(22) cm(-3)) with optical band gaps in the range of 2.2-2.5 eV for direct and 1.6-1.8 eV for indirect band gaps. Depending on the number of ALD cycles, multiphase compounds (made of digenite Cu1.8S, chalcocite Cu2S, djurleite Cu31S16 and covellite CuS) or single-phase digenite Cu1.8S films are obtained via a growth mechanism that involves in-situ copper reduction and loss of sulfur by evaporation. (C) 2016 Elsevier B.V. All rights reserved.