XPS Studies of Adsorption Sites on the Surface of Gas Sensitive Zinc Oxide Based Nanostructures

In recent years, approaches to study and control the adsorption sites on the surface of gas-sensitive materials have been actively developing. The specificity of chemical reactions and, consequently, sensor properties largely depend on the concentration and localization of active sites. The X-ray photoelectron spectroscopy technique affords the possibility to analyze the energy characteristics of a surface. Using this method, the effect of modification of sensor layers consisting of zinc oxide nanowires upon post-treatment in solutions of other metal (tin and iron) compounds on the chemical composition of their surface was analyzed. It was shown that under optimal technological conditions, the formation of ternary oxide compounds and a significant change in the ratio of oxygen in various bound states occur. It was demonstrated that such a change in the composition of the surface leads to a significant increase in the sensor response of the functional layers to isopropyl alcohol vapors.