Characterization of metal oxide-based gas nanosensors and microsensors fabricated via local anodic oxidation using atomic force microscopy

Abstract

Thiswork reports on nanoscale and microscalemetal oxide gas sensors, consisting ofmetal-semiconductor-metal barriers designed via scanning probe microscopy. Two distinctmetal oxides, molybdenum and titaniumoxides, were tested at different temperatures using CO2 and H2 as test gases. Sensitivities down to ppm levels are demonstrated, and the influence of dry and humid working atmospheres on these metal oxide conductivities was studied. Furthermore, the activation energy was evaluated and analyzed within working sensor temperature range. Finally, full morphological, chemical, and structural analyses of the oxides composites are provided allowing their identification as MoO3 and TiO2−𝑥x.