Effect of annealing on the structural, topographical and optical properties of sol gel derived ZnO and AZO thin films

TL;DR

This study investigates how annealing temperature affects the structural, topographical, and optical properties of undoped ZnO and Al-doped AZO thin films, revealing improvements in crystallinity and changes in optical transmittance.

Contribution

It provides a comparative analysis of ZnO and AZO thin films' properties as a function of annealing temperature, highlighting the effects of Al doping and heat treatment.

Findings

Crystallinity improves with higher annealing temperatures.

Annealing roughens film surfaces but AZO remains smoother than ZnO.

Optical transmittance decreases with increased annealing temperature.

Abstract

A comparative study of the physical properties of undoped Zinc Oxide (ZnO) and Al doped Zinc Oxide (AZO) thin films were performed as a function of annealing temperature. The structural properties were analyzed using X-ray diffraction and the recorded patterns indicated that the crystallinity of the films always enhanced with increasing annealing temperature while it degrades with Al doping. The topographical modification of the films due to heat treatment was examined by atomic force microscopy which revealed that annealing roughened the surface of all the films; however the AZO films always exhibited smoother morphology than ZnO. Study of the optical properties by UV-Visible spectrophotometer demonstrated that the transmittance was gradually diminished with the rise in annealing temperature. In addition, a notable increase in the optical band gap was also observed for the AZO films.