In this work, we report a p-Si/n-CeO2 junction diode fabricated by a cost-effective and large-area deposition technique of jet nebulizer spray pyrolysis. The n-CeO2 layer was coated on four different substrate temperatures (Tsub) 350, 400, 450, 500 °C and their properties were studied by various techniques like XRD, FE-SEM with EDX, UV–Vis and I–V characterization. XRD pattern confirmed a cubic fluorite crystalline phase of CeO2 thin films with preferential growth along (2 0 0) direction. A smooth surface with inter-connected smaller grains was recorded by FE-SEM micrographs and also the existing elements Ce and O have been confirmed. For Tsubof 450 °C, an exceptional optical absorption with smaller band energy of 3.3 eV was recorded in the UV–Vis spectrum. The electrical conductivity results indicated that all the films are semiconducting in nature. I–V characteristics of all the fabricated diode showed better rectification in dark with excellent photovoltaic characteristics under light exposed condition. The photosensitvity of the diode varied from 21.94 to 1093.75% with substrate temperature. Our results strongly suggested that rare-earth based p-Si/n-CeO2 diodes are suitable for future applications in ultraviolet photo-detector and photo-diode