Flexible Substrate Based Gas Sensors for Air Pollution Monitoring

Abstract

AbstractIn the given report we present results of investigation of possibility to produce gas sensors on flexible substrates (polymer roll base). As gas sensitive materials were chosen glass chalcogenide semiconductors on the base of solid solutions of (As2S3)x-(As2Se3)1−x (where x=0; 0.3; 0.5; 0.7 and 1.0) and also solid solutions of As-Tl-S-Se system. Thin films of the mentioned above materials were deposited on lavsan roll film by means of thermal evaporation under vacuum conditions 10-5 Torr. At the thickness of 1-2 um the deposited layers are possessed the specific resistance in the range of 1010-1014 Ohm.cm on dependence on chemical composition.The change of conductivity of these films in the presence of gas impurity in atmosphere was used as sensitive parameter. Gas sensitive characteristics of obtained structures were tested with such toxic and inflammable environmental pollutant gases as carbon monoxide, methane, nitrogen dioxide, hydrogen and other. All measurements of gas sensitivity were performed at room temperature. For further increase of the gas sensitivity and selectivity the very thin layer of Pd was deposited onto the surface of semiconductor layer. The last one has allowed to increasing the gas sensitive characteristics by order.Through routine technology mode ready gas sensors were created. Dimensions of the developed gas sensitive elements were 1000×1000×350 μm.