The Effect of Annealing on Structural, Electrical and Optical Properties of Al Doped ZnO (AZO) Spin-Coated Films

The investigation on the effect of different annealing temperatures on morphological, electrical, and optical properties of Al-doped ZnO (AZO) spin-coated films is presented here. The AZO thin films prepared by spin coating were deposited on the glass substrate at room temperature and post-heated at 300°C, 400°C, and 500°C. The thickness of the prepared films was about 160 nm. FTIR analysis identified Zn–O stretching around 400–600 cm⁻¹. The V-I curves displayed near-linear resistance trends, and resistivity increased from 1×10⁻⁵ Ω•cm to 3.1×10⁻⁵ Ω•cm, and the conductivity decreased, ranging from 8.46×104(Ω.cm)-1to 3.17×104(Ω.cm)-1with increasing annealing temperature. The optical transmittance of the films in the visible range was improved with increasing annealing temperature, while absorbance decreased. UV–Vis spectra showed 98.5% transmittance at 600 nm for the 500°C film. The optical bandgap slightly narrowed with the increment of annealing temperature.