Optical Properties of Aluminium-Doped Zinc Oxide Thin Films Synthesized via AACVD Using Nitrogen as a Carrier Gas

TL;DR

This study investigates how nitrogen-annealed aluminium-doped zinc oxide thin films, synthesized via AACVD, exhibit structural and optical property changes with varying aluminum content, highlighting their potential for optoelectronic applications.

Contribution

It provides new insights into the effects of nitrogen annealing and aluminum doping levels on the structural and optical properties of AZO thin films synthesized by AACVD.

Findings

Increased aluminum doping decreases crystallite size.

Nitrogen annealing enhances film absorbance and bandgap energy.

Optimal optical properties observed at 5-20% doping levels.

Abstract

The study uses AACVD technology with nitrogen carrier gas to make AZO thin films through which it determines structural, optical, and morphological changes from 0 to 20 percent aluminum doping. The depositions took place at 400 degrees Celsius on soda-lime glass before the samples received an annealing process at 450 degrees Celsius inside a nitrogen chamber. The X-ray diffraction analysis identified superior crystalline structure in films processed with nitrogen gas through their strong signals at the 220, 311 and 222 peaks. The increasing levels of aluminum doping decreased the crystallite dimensions and elevated grain boundary concentrations because of intensified crystal tension and defective structural formation. The profilometry assessment determined film thickness increased mildly from 102 nanometers in undoped ZnO to 115 nanometers in 20 percent aluminum-doped ZnO. The presence of nitrogen annealing in the films led to increased absorbance while the strongest absorbance peaks occurred when the material contained 5 percent dopants. The bandgap energy expanded through the change from undoped ZnO with 3.21 electron volts to 3.33 electron volts at 20 percent aluminum doping which matched Burstein-Moss effect results. The optoelectronic devices gain enhanced optical characteristics from the doping levels exceeding 15 percent.