Heterojunctions based on p-CuO/n-ZnO, prepared by simple methods such as spin coating, normally exhibit low photoconversion efficiencies, and need modification. Doping the ZnO layer with various ions such as Sn4+ could be a solution. In this work, the heterojunctions have been prepared by two simple methods. To prepare the CuO@ZnO junction, by method 1, the n-ZnO layer has been spin-coated on tin-doped indium oxide/glass substrates (ITO/glass) followed by spin coating of the p-CuO layer. To prepare the ZnO@CuO/Cu sheet junction, by method 2, the p-CuO layer has been prepared by thermal oxidation of Cu metal sheet, followed by spin coating of ZnO. In both cases, the ZnO film has been doped with Sn4+ ions at 1.5% concentration by mole. Sn-doping effects, on structural and morphological properties of the junction, have been comparatively studied by X-ray diffraction and atomic force microscopy. In both preparations, doping affects optical, electrical and photovoltaic (PV) properties. Preparation method also affects junction characteristics, as preparation method 2 shows heterojunctions with higher PV characteristics. The results show inroads to improve PV characteristics for the heterojunction based on the proper preparation method and Sn doping