Abstract:
Aluminium-doped zinc oxide (AZO) thin films and ZnO nanorods (NRs) were synthesized
and characterized to explore their structural, optical, and electrical properties. AZO seed
layers with varying Al concentrations 2, 3, 5, and 8 mol% were deposited on soda-lime glass
via spin coating, followed by hydrothermal growth of ZnO NRs. XRD and SEM confirmed
vertically aligned, c-axis-oriented nanorods, with morphology influenced by doping and
annealing temperature. Optimal crystallinity was achieved at 250 °C, while higher
temperatures led to lattice relaxation and reduced structural quality.
Photoluminescence revealed UV near-band-edge emission (~380 nm) and visible deep-level
emission (500–700 nm), with DLE intensity suppressed at 8 mol% doping, indicating
reduced defect density. Both AZO and ZnO NRs showed high optical transparency, and
band gaps ranged from 3.44–3.55 eV (AZO) and 3.05–3.15 eV (ZnO NRs), tunable via Al
doping. The electrical conductivity and film thickness were strongly influenced by both Al
concentration and annealing conditions. The favorable combination of structural integrity,
high transparency, tunable band gaps, and improved conductivity renders these AZO/ZnO
nanostructures promising candidates for application in a wide range of optoelectronic
devices.
