Copper oxide (CuO) is a nanostructured semiconductor material with the potential for solar energy conversion and can be suitable for solar cells when used as a thin film. Herein, nondoped and doped (doping ratios of 1%, 2%, and 3% zirconium [Zr]) CuO thin films on silicon (Si) with the spin-coating technique are developed. Optical and topological characterizations of CuO thin films are examined by ultraviolet-visible and X-ray diffraction. The electrical properties of nondoped and Zr-doped CuO/Si heterojunctions are investigated with experimental current–voltage measurements in the dark and under illuminated conditions. The electrical behavior of nondoped and Zr-doped CuO/Si heterojunctions is obtained using the experimental J–V technique and computational Cheung–Cheung and Norde methods. A simulation based on nondoped and Zr-doped CuO/n-Si heterojunction solar cells using SCAPS-1D is completed. Photovoltaic (PV) parameters of experimentally produced and theoretically calculated CuO and Zr-doped CuO/Si heterojunction solar cells are compared. Accordingly, PV parameters of 1% Zr-doped CuO/Si solar cells show the highest power conversion efficiency calculated as a function of interfacial defect density and hole carrier concentration.