Cosputtered SnO₂–ZnO composite nanofilms with improved dual function

Abstract

SnO 2 -ZnO composite thin films were grown by radio-frequency and directcurrent cosputtering of ceramic ZnO and metallic Sn targets, respectively. During the cosputtering film growth, the SnO 2 matrix sputtering power was fixed at 20 W, while the additive ZnO sputtering power was varied in the range of 40-80 W. Structural and compositional analysis results showed that the ZnO sputtering power increased the relative ZnO phase content in the composite film and its surface grain size. Compared to the single-constituent compounds, the as-synthesized SnO 2 -ZnO composite films exhibited enhanced photoelectrocatalytic performances for the degradation of methyl orange dyes under irradiation.The SnO 2 -ZnO composite film obtained at a ZnO sputtering power of 60 W (SZ60; Zn/Sn = 11.2%) exhibited the highest photoelectrocatalytic activity among the various samples. In addition, SZ60 exhibited superior ethanol gas-sensing performances among the various thin-film sensors. Owing to the formation of a suitable number of SnO 2 /ZnO heterojunctions, SZ60 exhibited a highly efficient photo-induced charge separation and appropriate potential barrier height to improve the gas-sensing ability. The experimental results demonstrate a promising approach to design oxide composite films with desirable photoelectrocatalytic and gas-sensing functions by controlling the relative content of ZnO and SnO 2 in the composite film through a cosputtering process.

Enhanced photoactive performance of three-layer structured Ag/Cu2O/TiO2 composites with tunable crystal microstructures

“…In addition, among the various photocatalysts, CTA100 has the best photodegradation ability towards MO solution under the given test conditions. Comparatively, CTA100 can degrade 52% MO solution in this study after 30 min irradiation, and this degradation level is superior to that of the SnO 2 -ZnO nanofilm prepared with a ZnO sputtering power of 40 W (degradation level: 43%) 40 and the ZnS-Ag 2 S heterostructure prepared with an Ag sputtering duration of 80 s (degradation level: 40%) 41 under similar test conditions. The results show that the photocatalytic ability of the as-synthesized Ag/Cu 2 O/ TiO 2 films herein is comparable with that of other composite material systems.…”

“…Notably, a higher photocurrent density means that the photogenerated charges of the sample have better separation efficiency. 40,41 All the CT series composite films exhibit better photoresponse performance than the pristine TiO 2 film. The modification of Cu 2 O as a visible light catalyst strengthens the lightcollecting ability of the TiO 2 template film; furthermore, the p-n heterostructure in the composite system improves the separation efficiency of photogenerated carriers.…”