Self-Powered Photodetector with High Sensitivity Based on a CeO₂/TiO₂ Thin Film

Abstract

This work reports the growth of a CeO2/TiO2 thin film (TF) using an electron beam evaporator for photodetector application. Field emission gun scanning electron microscopy confirms the uniform growth of CeO2/TiO2 TF. The CeO2/TiO2 TF device exhibited excellent rectification characteristics under dark and light illumination conditions. Under illumination, the generation of photocurrent arises from the effective separation of photogenerated electron–hole pairs within the built-in electric field at the interface of the CeO2/TiO2 TF device. It was found that the fabricated device exhibits a dark current of 5.4 × 10–10 A, a sensitivity of 732, and a rectification ratio of 556. The maximum response of the devices is observed at 260 nm with a responsivity of 4.5 mA/W at a zero bias voltage. A comparable detectivity of 3.4 × 1011 Jones was also calculated. Moreover, the rise time and fall time were found to be 1.1 and 0.1 s, respectively. The obtained results of CeO2/TiO2 TF devices render them highly suitable for applications demanding high response and self-sufficient functionality.