Micro-gas-sensor with conducting polymers

A study on semiconductor-based sensing layers deposited via thick-film method was carried out, with emphasis on achieving nanosized films through proper processing and studying their morphological and structural features. Screen-printing is a valuable method for deposition of sensing thick-films over either conventional substrates or recently-developed micromachined hotplates. The preparation of a suitable material for deposition was highlighted through titania as a practical example. Nanostructured titania powders could be stabilized for long-term operation by doping. As an example of the electrical performance, the response of the sensor to CH4 was shown. The response of the sensor towards different concentrations of CO, NO2, and CH4 showed that it was mostly sensitive to NO2 within 0-0.1 ppm, i.e., for environmental monitoring. The integration of the thick-film method with Si-micromachining processing opens up prospects for large-scale production of hybrid devices featuring low power consumption and reduced dimensions