Study the characterization of ZnO and AZO films prepared by spray pyrolysis and the effect of annealing temperature

Abstract

Spray-pyrolysis was used to successfully create ZnO and AZO (Al-doped ZnO) thin films on glass substrates at various annealing temperatures. Structure, morphology, and optical characteristics were investigated in relation to doping and annealing temperature using analytical techniques such as FTIR, UV–Vis spectroscopy, XRD, and FE-SEM. The films' singular-phase polycrystalline hexagonal Würtzite structure was revealed by XRD data, and the crystallographic plane for both AZO and ZnO was (0 0 2). Crystallite sizes are increased by raising the annealing temperature and adding Al-doping, which enhances surface morphology. where the diameters of the AZO crystallites expanded from 23.3 to 33.3 nm, whereas the ZnO crystallites grew from 27.8 to 28.5 nm. Scanning electron microscopy's morphology reveals that the surface particles' tiny, round shapes have changed to spherical clusters that resemble cauliflowers with increasing annealing temperatures. Notably, the ZnO film has a high transmittance, whereas the AZO film has a relatively low transmittance. Furthermore, at an annealing temperature of 400 °C, all films show notable absorbance, with the highest absorption seen at 400 and 413 nm for ZnO and AZO, respectively. The bandgap values at various annealing temperatures vary from 3.22 to 3.23 eV and 3.08–3.12 eV for ZnO and AZO, respectively. As the annealing temperature rose, the phenomena showed a drop in value.