Substrate critical effect on the structural and H2 Gas sensing characteristics of solution-processed Zn0.075Cu0.025O films

Abstract

In this study, we report the synthesis of Zn _0.075 Cu _0.025 O films by chemical bath deposition to determine the effect of substrate (glass slide or ZnO seed layer) on the structural and H _2 gas sensing properties of the produced films. The crystal phase, structural topography, surface morphology, and functional groups of the as-synthesized films as well as H _2 gas sensing properties were investigated. Although both films have a hexagonal wurtzite structure, ZnO seed layer-based Zn _0.075 Cu _0.025 O film is more crystalline than glass slide-based Zn _0.075 Cu _0.025 O films. ZnO seed layer-based Zn _0.075 Cu _0.025 O films exhibited much more nanorod and fewer nanosphere forms compared to glass slide-based Zn _0.075 Cu _0.025 O films. EDX analysis and Raman spectra of both samples confirmed the presence of defects in Cu: ZnO samples. ZnO seed layer-based sensors showed higher response (140%) and lower operating temperature (80 °C) compared to glass slide-based sensors (87% response and 140 °C operating temperature). The most important thing to note here is that the fabricated sensors exhibited a high response at room temperature. The responses at room temperature were found as 46% and 23% for the ZnO seed layer-based and glass slide-based sensors, respectively. Sensors operating at room temperature are especially important for commercial applications.

Keywords

• metal oxides
• chemical bath deposition
• H2 gas sensing
• resistive sensor