Preparation of AZO/Cu/AZO films with low infrared emissivity, high conductivity and high transmittance by adjusting the AZO layer

• Low-emissivity transparent AZO/Cu/AZO films were prepared by magnetron sputtering. • The performance of AZO/Cu/AZO films were optimized by adjusting AZO layer. • Low emissivity and high visible transmittance were achieved simultaneously. • Bottom AZO layer is helpful to the growth Cu layer and top AZO layer. AZO/Cu/AZO films were prepared on glass substrates by direct-current magnetron sputtering at room temperature. The effects of the AZO layer on the infrared emissivity and photoelectric properties of AZO/Cu/AZO films were studied. The results show that the infrared emissivity and sheet resistance of the AZO/Cu/AZO films decrease with the AZO layer thickness, and then increase when further increasing the thickness to 40 nm. Meanwhile, the visible transmittance first increase and then decrease slightly. The multilayer film with 40 nm-thickness AZO layer shows the lowest sheet resistance of 9.96 Ω/sq, lowest infrared emissivity of 0.055 and high transmittance of 87.7 %. The sheet resistance and infrared emissivity are associated with the quality of top AZO layer and Cu layer. The bottom AZO layer with optimized thickness is beneficial to the growth of middle Cu layer and top AZO layer, which is facilitate to improve the performance of multilayer films.