Localized aerosol-assisted CVD of nanomaterials for the fabrication of monolithic gas sensor microarrays

Abstract

The self-heating capability of MEMS-based devices is used to grow locally into the sensing active area of monolithic gas sensor microarrays differently-functionalized materials via aerosol-assisted CVD. Results derived from SEM, TEM, XRD and Raman demonstrate the integration of non-functionalized (WO3−x) and functionalized nanostructures with gold (WO3-x/Au) or platinum (WO3-x/Pt) NPs into the array. Tests of these microarrays toward various concentrations of reducing gases show stable and reproducible responses, with the highest responses (R) for WO3−x to carbon monoxide (e.g. R=4.3–80ppm), for WO3−x/Au to ethanol (e.g. R=7–80ppm) and for WO3−x/Pt to hydrogen (e.g. R=3.6–80ppm). Principal component analysis of the sensor response replicates to each gas and concentration suggest that the differences in the sensing properties of each element of the array provide the complementary information to discriminate H2 and EtOH from CO.