Green light activated hydrogen sensing of nanocrystalline composite ZnO-In₂O₃ films at room temperature

The possibility of reducing the operating temperature of H₂ gas sensor based on ZnO-In₂O₃ down to room temperature under green illumination is shown. It is found that sensitivity of ZnO-In₂O₃ composite to H₂ nonmonotonically depends on the oxides' content. The optimal ratio between the components is chosen. The new mechanism of nanocrystalline ZnO-In₂O₃ sensor sensitivity to H₂ under illumination by green light is proposed. The mechanism considers the illumination turns the composite into nonequilibrium state and the photoconductivity change in the H₂ atmosphere is linked with alteration of nonequilibrium charge carriers recombination rate.