Fabrication and photosensitivity of ZnO/CdS/Silica nanopillars based photoresistor

Abstract

A kind of Zinc oxide (ZnO)/Cadmium sulfide (CdS)/Silica nanopillars structure is fabricated to photoresistor for the first time. The silica wafer with countless nanopillars is used as the substrate for photoresistor. CdS and ZnO film are deposited by frequency (RF) magnetron sputtering onto the silica nanopillars surface to form ZnO/CdS/Silica nanopillars structure. The ZnO nanowires also can grow on the CdS surface by the hydrothermal reaction to ZnO nanowires/CdS/Silica nanopillars structures. The X-ray diffraction curves show that the ZnO and CdS film both on the planar silica and nanopillar silica surface are well-crystallized. The ZnO film deposition can reduce the reflection and increase the absorption of the incoming light, especially for the light with a wavelength less than 350 nm. And the ZnO/CdS heterojunction structure can retard the recombination probability of the photon-generated carries and prolong the lifetime of the photon-generated carriers, which lending to a remarkable photocurrent improvement. The photosensitivity property testing results show that the ZnO nanowires/CdS/Silica nanopillars structure has the best photosensitivity response of 135 for the white light with 10 mW/cm2 illumination.