Investigation of sol-gel prepared CeO2-TiO2 thin films for oxygen gas sensing

The oxygen gas sensing performance of semiconducting CeO2-TiO2 thin films have been investigated. These thin films have been prepared by the sol-gel process utilizing a non-alkoxide as the main precursors. For gas sensing measurements, the films were deposited by the spin coating technique onto alumina substrates with interdigital transducers located on the top and a micro-heater on the bottom. For the microstructural characterization, the thin films were deposited onto single crystal silicon substrates. X-ray photoelectron spectroscopy (XPS), Auger electron spectrometry (AES) and scanning electron microscopy (SEM) were employed to analyze the films. These films were exposed to various concentrations of O2 gas and their electrical responses were measured

Investigation of sol-gel prepared Ga-Zn oxide thin films for oxygen gas sensing

Gallium oxide-zinc oxide (Ga2O3-ZnO) thin films have been prepared by the sol-gel process and their oxygen gas sensing performance has been investigated. These semiconducting films were deposited on alumina substrates with interdigital electrodes and single crystal silicon substrates for the electrical and microstructural characterization. X-ray photoelectron spectroscopy (XPS) showed that the actual concentrations of Ga and Zn thin films differ from the nominal values in the prepared solutions. Additionally, the concentration of ZnO decreases when the annealing temperature increases. Scanning electron microscopy (SEM) revealed that films with Ga/Zn atomic ratio 90:10 possess cracks and are inhomogeneous when compared to those with that of 50:50. The sensors with Zn 50 at.% had a much larger response at lower operating temperature (<430 °C) compared to the Ga-dominated sensors, which operate above 450 °C. Furthermore, these sensors showed greatest performance at temperatures in the range of 380-420 °C. It was found that by increasing the amount of ZnO in the thin film sensors, the operating temperature decreased as well as the base resistance

Investigation of thin films of mixed oxides for gas-sensing applications

Recently, the thin films of some mixed metal oxides (Mo, Ti, Sn, W, etc.) have been indicated as very promising materials for gas-sensing applications. Nevertheless, there is still a significant lack of experimental information on these compounds, where the surface properties can be defined not only by their chemical composition but also by the nanosized morphology of the films. In this study we report the results of XPS investigations of Mo-Ti, Mo-Sn and Mo-W oxides. The films of mixed oxides with different composition ratios were prepared by sol-gel and magnetron sputtering techniques. The gas sensitivity of the films at different temperatures was studied by measuring the electrical response to typical gases. Selected-area XPS depth profiling of the samples was carried out by using cyclic Ar+ sputtering. The separation of different chemical species of the same element and quantitative analysis of experimental depth profiles enabled us to reveal completely the chemical composition of the films investigated. In such a way, the samples of mixed oxides, prepared by two different techniques and annealed at different temperatures (450-700°C), were characterized and compared

Investigation of sol-gel prepared CeO2-TiO2 thin films for oxygen gas sensing

The oxygen gas sensing performance of semiconducting CeO2-TiO2 thin films have been investigated. These thin films have been prepared by the sol-gel process utilizing a non-alkoxide as the main precursors. For gas sensing measurements, the films were deposited by the spin coating technique onto alumina substrates with interdigital transducers located on the top and a micro-heater on the bottom. For the microstructural characterization, the thin films were deposited onto single crystal silicon substrates. X-ray photoelectron spectroscopy (XPS), Auger electron spectrometry (AES) and scanning electron microscopy (SEM) were employed to analyze the films. These films were exposed to various concentrations of O2 gas and their electrical responses were measured. (C) 2003 Elsevier B.V. All rights reserved