Fabrication of Aluminium-Doped Zinc Oxide (AZO) Thin Films Using Nitrogen as a Carrier Gas in Aerosol-Assisted Chemical Vapour Deposition (AACVD)

This study investigated the fabrication of Aluminium-doped Zinc Oxide (AZO) thin films via Aerosol-assisted Chemical Vapour Deposition (AACVD) technology using Nitrogen as the carrier gas, with their structural, optical, and morphological properties examined across different Aluminium-doping levels, ranging from 0% to 20%. The deposition process was carried out at a temperature of 400°C, which was proceeded by annealing at a temperature of 450°C in a Nitrogen environment. The X-ray Diffraction (XRD) analysis confirmed a high crystallinity with strong peak signals at (100), (110), (200) and (222) planes. An increase in Aluminium-doping level led to smaller crystallites and higher dislocation densities due to enhanced lattice strains and structural defects. UV absorbance analysis revealed higher peak intensities, especially in samples with 5% or lower doping. The ZnO bandgap energy increased from 3.36 eV in pristine ZnO to 3.78 eV at 20% Al doping, influenced by the Burstein–Moss effect. A broadened optical activity range was observed at doping levels above 15%, enhancing the films’ potential for optoelectronic applications. The usage of Nitrogen carrier gas led to higher dislocation densities and slight increases in film thickness. With a tuned optical bandgap and high transparency at specific doping levels, these AZO films are well-suited for transparent conductive oxide (TCO) applications, including solar cells, display technologies, and smart windows.