The features of thin film and ceramic sensors at the detection of CO and NO2

Properties of In2O3, In2O3–SnO2 and In2O3–NiO ceramic and thin film sensors formed starting from colloidal solutions for the detection of CO and NO2 are compared. Obtained results are discussed taking into account the redox mechanism of the conductivity changes. The additives affect gas-sensitive properties of In2O3 in two ways: (i) changing the activity of In2O3 when interacting with analyzed species by the change of Fermi energy, and (ii) directly participating in a chemical reaction with analyzed species.