A facile fabrication of Sn-doped CeO_2 nanocrystalline thin films with enhanced photodiode properties for optoelectronic applications

摘要

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 CeO_2 thin films assembled through spray pyrolysis technique to enhance the p-Si/n-Sn:CeO_2 diode performance. A polycrystalline nature of cubical crystal structured Sn-CeO_2 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 CeO_2 system was confirmed by the EDX and XPS spectrum. The effect of Sn doping on the optical absorption and band gap of CeO_2 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:CeO_2 diode was fabricated, and its performance was analyzed under dark and light intensity of 100 mW/cm~2. 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 CeO_2.