Aging effect of the precursor solution on the structural, morphological, optical and electrical properties of ternary CdZnO thin films suited for optoelectronic applications

Precursor solution aging effect on the physical properties of ternary CdZnO thin films is reported in this paper. Nanostructured CdZnO thin films were fabricated on glass substrates by spray technique using perfume atomizer from fresh precursor solution and from solutions with different aging periods (1, 2, 3 and 4 days). XRD studies confirm the polycrystalline nature of the films. All the films exhibit cubic crystal structure with a strong (1 1 1) preferential orientation irrespective of aging period of the starting solution. The CdZnO film prepared from 3 days aged solution possess a high crystallite size value of 38.72 nm and low strain and dislocation density values of 0.89 × 10−3 and 0.667 × 1015 lines/m2 respectively which supports for its enhanced crystallinity. Cauliflower shaped nanostrucutres are observed for all the films from the SEM images and the CdZnO film prepared from 3 days aged precursor solution exhibit better surface morphology. Optical band gap decreased with increase in aging period of the starting solution which was attributed to quantum confinement effect. Electrical resistivity of the CdZnO films decreased with aging period and the film coated from 3 days aged solution exhibited a minimum resistivity of 0.056 × 10−2 Ωcm.