Influences of film thickness and annealing temperature on properties of sol–gel derived ZnO–SnO₂ nanocomposite thin film

Graphical abstract: - Highlights: • Prepared zinc–tin–oxide (ZTO) thin films on glass substrates by a spin-coating method. • The effects of film thickness and annealing temperature on the structural, morphological, electrical, and optical characteristics were investigated. • ZTO thin films are suitable for use as transparent electronic devices by adjusting the film thickness and annealing temperature. - Abstract: In this study, ZnO–SnO₂ nanocomposite thin film was prepared on glass substrates with different film thicknesses and annealing temperatures through a sol–gel method. From the results of thermogravimetric analysis (TGA), it was deduced that the ZnO–SnO₂ thin film could be sufficiently formed at approximately 500 °C. The XRD patterns showed enhanced crystallinity of the ZnO–SnO₂ thin film with increasing film thickness and annealing temperature. However, it was also revealed that the crystallinity deteriorated when the film thickness and annealing temperature are 270 nm and 700 °C, respectively. The variation in electrical resistivity corresponded to intensities of the (0 0 2) diffraction peaks shown in the XRD patterns. It was also found that the increase of film thickness and annealing temperature led to rougher surface morphology and to an increase in grain size. The optical properties deteriorated with increasing film thickness and annealing temperature of the ZnO–SnO₂ thin films