Effect of Al-Doping on the Structure and Optical Properties of ZnO Thin Films by Sol-Gel Spin Coating

Abstract

Zinc oxide (ZnO) and Aluminium-doped zinc oxide (AZO) thin films were successfully synthesized using the sol-gel spin coating technique. The synthesis of pure phase of ZnO thin films with Polycrystalline-hexagonal wurtzite structure and characterized by lattice parameters (a=3.194Ao and c=5.194Ao) using XRD analysis. There is No significant changes in phase structure were observed upon aluminium doping. The crystallite size, lattice constants, and strain remained nearly unchanged with increasing Al concentration, suggesting that Al ions substitute interstitially at Zn sites in the ZnO lattice an inference supported by EDX analysis. surface morphology Al doping levels up to 3 wt% to 5 wt% films exhibited a nanowire-like structure and reduction in grain size that indicates aluminium incorporation influences the film's growth and surface characteristics. UV-Vis Spectroscopy results indicate that the optical band gap of ZnO thin films decreases from 3.288 eV in the undoped state to 3.178 eV with increasing Al doping concentration.