Influence of the annealing conditions on the properties of ZnO thin films

Abstract

The effect of annealing treatment (in the presence of different types of atmospheres) on the performances of zinc oxide thin films (intrinsic and doped with In and Al) prepared by spray pyrolysis have been studied, with the aim to determine more adequate conditions to improve the properties of the films. The results show that the annealing treatment leads to substantial changes in the structural, electrical and optical characteristics of ZnO thin films. The most significant improvements were obtained after annealing in forming gas (reduction atmosphere) at 200°C during 2 h. The ZnO:In film after heat treatment was the one that exhibited the lowest resistivity (ρ=5.2×10⁻² Ωcm) and a high transmittance (T=86%).