Effects of SiO2 layer on transparent conductivity and infrared property of AZO/Cu/AZO/SiO2 films

AZO/Cu/AZO/SiO2 films were sputtered on glass substrates at room temperature. Effects of SiO2 layer on structure, conductivity and solar control performance of AZO/Cu/AZO/SiO2 films were investigated. The SiO2 layer is useful to the growth of AZO grains in the top layer, improvement of conductivity and blue shift of transmission spectrum. With the increase of SiO2 layer thickness, the sheet resistance decreases first and then increases, band gap increases and near-infrared barrier rate first increase significantly and then decrease slightly. When the SiO2 layer thickness is 36 nm, the multilayer film possesses lowest sheet resistance of 8.73 Ohm/square, the lowest infrared emissivity of 8–14 μm is 0.048, highest near-infrared barrier rate of 60% and high transmittance of 81.2%. Both the change of conductivity and the increase of band gap make the ability of multilayer film to block near-infrared light improve significantly.