DEVELOPMENT OF SELECTIVE SEMICONDUCTOR SENSORS OF HYDROGEN SULFIDE, AMMONIA, AND METHANE USING NANOMATERIALS OBTAINED BY THE SOL-GEL PROCESS
Abstract
In a wide range of changes in the concentration of the initial components, the influence of the components of the initial substances on the patterns of formation of a gas-sensitive material was studied. It was found that the initial solution has the highest stability (18.5 days) at the ratio of contents: TEOS: water: ethanol: HCI=1:20: 30: 0.05. As a result of the study of the regularities of sol-gel synthesis of semiconductor gas-sensitive materials based on tetraethoxysilane and metal oxides Zn, Ti, and W, the following highly efficient gas-sensitive materials were selected, and the optimal operating temperature for the sensitive elements of semiconductor sensors H2S, NH3, and CH4: H2S (topt.=350°C; 95WO3+5CuO), NH3 (topt.=350 °C; 95TiO2+5Fe2O3), CH4 (topt.= 400°C; 90ZnO+10CoO). The results obtained were used in the development of thin-film semiconductor ssensors for H2S, NH3, and CH4 with a substrate based on a spiral of a glazed platinum microwire. The metrological parameters of sensors based on gassensitive materials synthesized with and without a template (polyethylene glycol) were studied during the experiments. It has been found that the sensitivity of a metal oxide composite film obtained in the presence of a template in the determination of H2S, NH3, and CH4 is higher than that of a film obtained without a template.