Ultra-high photocurrent response in a chromia oxide thin film under visible light illumination

In this work, the photoconductivity of chromia (Cr2O3) thin films, which were configured an in-plane electrode, was investigated under visible laser illumination. The fast and slow response components of photocurrent were originated by its exciting defect level. Surprisingly, a high photoresponsivity up to 1.94 × 103 A/W was obtained when the Cr2O3/Pt planar capacitor was applied an incident wavelength of 650 nm at room temperature. Moreover, dielectric characterization implied that the current of channel in Cr2O3 film increased with the increasing of its defects concentrations under laser illumination. Our results indicate that the Cr2O3 thin films have a potential application in the photoelectric field. •Cr2O3 film has a potential in photoelectric devices application.•High photoresponsivity of 1.94×103 A/W and internal photogain of 3.7×103 are obtained in Pt/Cr2O3/Pt structure.•Photocurrent time characteristics with fast and slowly varying components is arising from defect level excitations.•Ac field response of dielectric constant in a Pt/Cr2O3/Pt structure was observed.