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Traditional methods of synthesis of metal-oxide gas sensing materials for semiconductor sensors are based on wet sol-gel processes. However, these processes lead to the formation of hydroxyl groups on the surface of oxide particles being responsible for the strong response of a sensing material to humidity. In this work, we investigated the possibility to synthesize metal-oxide materials with reduced sensitivity to water vapors. Dry synthesis of SnO 2 nanoparticles was implemented in the gas phase by spark discharge, which allowed us to produce powder with specific surface area of about 40 m 2 /g after additional annealing at 610 °C. The drop of sensor resistance does not exceed 20%, when air humidity increases from 40 to 100%, whereas the response to 100 ppm of hydrogen is of a factor of 8 with very short response time of about 1 s. [ABSTRACT FROM AUTHOR]

Abstract: We present the first results on CO2 gas detection with the help of sensors based on metal-polymer electrolyte-isolator-semiconductor structure with additional layer of proton conducting solid electrolyte – ether of phenylsulphonic acid and polyvinyl alcohol. The sensor operates at room temperature. The detection limit is shown to be of about 100ppm of CO2 in air. [Copyright &y& Elsevier]