The electrical and photovoltaic properties of the nanostructure ZnO/p-Si diode have been investigated. The nanostructure ZnO/p-Si diode was fabricated using sol–gel spin coating method. The ideality factor and barrier height of the diode were found to be 3.18 and 0.78eV, respectively. The obtained n ideality factor is higher than 2, indicating that the diode exhibits a non-ideal behavior due to the oxide layer and the presence of surface states. The nanostructure of the ZnO improves the quality of ZnO/p-Si interface. The diode shows a photovoltaic behavior with a maximum open circuit voltage V oc of 0.26V and short-circuits current I sc of 1.87×10 −8 A under 100mW/cm 2 . It is evaluated that the nanostructure ZnO/p-Si diode is a photodiode with the obtained electronic parameters.