Modelling and Characterisation of Co3O4 Thin Film Gas Sensors

AbstractGas sensing properties of Co-oxide thin films were investigated and modelled. The films of cubic Co3O4 structure and with thickness between 20-150 nm were fabricated by pulsed laser deposition. The response of dc-conductivity to different gases (CO, NO2, CH4) was tested at temperatures 240 - 400 °C, and at different oxygen pressures. The conductivity changes due to O2 and due to test gas were found to be almost independent. The commonly used ionosorption model, which assumes reactions with adsorbed oxygen ions, failed to describe the dataset obtained at different CO and O2 pressures. Alternative mechanisms are discussed