In this study, atomic layer deposition (ALD) of Cu2S was explored using bis(dimethylamino-2-methyl-2-butoxy)copper(II) and 5% H2S combination as Cu and S sources, respectively. The reaction resulted in a high growth rate of similar to 0.22-0.24 nm/cycle at 150-200 degrees C owing to the high reactivity of the Cu precursor. At all investigated temperatures, Cu2S films with Cu oxidation state of +1 were obtained with negligible impurity levels. It was revealed that stoichiometric Cu2S films could be deposited at 120-150 degrees C, while sulfur deficient films was formed at 200 degrees C. Cu2S ALD process at low temperatures of 100-120 degrees C resulted in continuous film formation while the higher deposition temperatures of >150 degrees C led to island formation. Cu2S films showed p-type electrical characteristic with high hole concentrations of 4 x 10(19)-10(21) cm(3) and Hall mobility of 2 cm(2)/vs. Lastly, the as-deposited Cu2S films exhibited an optical band gap of 1.2 eV which widened upon prolonged surface oxidation and in addition displayed NIR intra-band absorption. (C) 2018 Published by Elsevier B.V.