Influence of the power density and working pressure in the magnetron co-sputtering deposition of ZnO–SnO2 thin films and their effect in photocatalytic hydrogen production

Abstract

This work presents the photocatalytic hydrogen production of ZnO–SnO2 thin films deposited by the magnetron co-sputtering technique varying the deposit conditions as power density and working pressure. As the power density of Sn increase, it was observed an increase in the presence of the SnO2 orthorhombic phase. Because of this increase, the number of defects generated in the films increases as it was corroborated by PL and XRD results. On the other hand, when the films were deposited at different working pressures, more significant optical and physicochemical changes were observed. The XRD results could be verified revealed that the working pressure could control the preferential orientation of the ZnO phase in the films. The working pressure also influenced the presence of two different SnO2 phases (orthorhombic and tetragonal). The surface roughness is also affected by the various working pressures since it increased when the deposits were made at low working pressures. The decrease in the roughness affects the transmittance percentage of the films, decreasing these to affecting the pass of the visible light. The photocatalytic efficiency was influenced by different structural defects that can act as electron traps or recombination centers.