A thin-film photovoltaic device and a process of making such a device, the device comprising a first layer of a chalkopyrite semiconductor of a first doping type; a second layer of intrinsic zinc oxide deposited by chemical vapour deposition; a third layer of zinc oxide semiconductor of a second doping type opposite to the first doping type and deposited by a method other than chemical vapour deposition; and wherein the second layer is arranged between the first and third layers.