The advancement of p–n photodiode fabrication employing rare-earth materials has created cogent interest in the field of semiconductor device technology. We report on the formation of pure and Sn-doped CeO2 thin films assembled through spray pyrolysis technique to enhance the p-Si/n-Sn:CeO2 diode performance. A polycrystalline nature of cubical crystal structured Sn-CeO2 thin films was developed on glass slides with various doping levels of tin (0, 2, 4 and 6 wt%). The crystallite size was found to decline with increasing Sn wt%. A uniform surface with tiny spherical-like crystallite grains was observed through the FE-SEM microscope. The existence of Sn ions with the CeO2 system was confirmed by the EDX and XPS spectrum. The effect of Sn doping on the optical absorption and band gap of CeO2 was evaluated, in which the 2 wt% Sn exhibited lower Eg value with maximum absorption. The Sn ions enhanced the electrical conductivity suggesting the semiconducting nature of the films. The p-Si/n-Sn:CeO2 diode was fabricated, and its performance was analyzed under dark and light intensity of 100 mW/cm2. The photosensitivity of the device varied from 17.11 to 671.65%. The ON–OFF photoresponse of 6 wt% Sn is relatively higher than that of pure CeO2.