Optimization of photoelectric properties and temporal stability of AZO/Ti/Cu/AZO films by insertion of Ti layer for low emissivity applications

Low infrared (IR) emissivity of AZO/Ti/Cu/AZO films with four-layer structure were deposited on glass substrate. IR emissivity, optoelectronic properties and temporal stability of AZO/Ti/Cu/AZO film was investigated with increasing Ti layer thickness. The results suggest that the appropriate Ti layer thickness is beneficial to improvement of crystalline of the AZOtop layer, which contributes to further enhancement of the optoelectronic and infrared properties of the films. The films with 10 nm-thickness Ti layer show lowest infrared emissivity of 0.045, high visible-transmittance of 87.3 %, lowest sheet resistance of 8.10 Ω/sq and figure-of-merit of 3.17 × 10-2 Ω−1. Meanwhile, Ti layer can effectively avoid oxidation of Cu layer and improve the temporal stability of film. After prolonged exposure to air, IR emissivity of film is still at 0.050 and visible-transmittance is 87.0 %. The AZO/Ti/Cu/AZO films with low IR emissivity and excellent temporal stability have great potential for application in the field of low-emissivity films.