Enhanced response speed of TiO2 nanoarrays based all solid-state ultraviolet photodetector via SiO2 dielectric layer

Abstract

All solid-state ultraviolet photodetector based on TiO2 nanoarrays always suffers from slow response speed, which seriously limits its actual application. In this work, a novel all solid-state hybrid structure ultraviolet photodetector based on nano-tree TiO2 nanoarrays and SiO2 dielectric layer was prepared. The response speed of the device can be improved significantly by the addition of SiO2 layer. The obtained TiO2/SiO2 hybrid device demonstrates large responsivity of 1.15 A/W, high detection sensitivity of 7.74 × 1013 Jones and fast photoresponse time of 1.13 s/0.75 s for PD4 under UV light illumination. The existence of the SiO2 layer widen the depletion layer on the surface of TiO2, which increases the loss rate of the photo-generated carrier and reduces the response time of the device. This device based on nano-tree TiO2 nanoarrays and SiO2 layer provides a certain fundamental for the future development of all solid-state photodetectors.