Effect of annealing on the characteristics of nanocrystalline ZnO thin films

Abstract

Nanocrystalline ZnO thin films with homogenous surface morphology and particle size were grown on p-type silicon (100) substrate by thermal evaporation method. The films were subsequently annealed at different temperatures for studying the effect of thermal treatment on the surface morphology of the films. The study of atomic force microscope (AFM) images reveals that the film comprises uniform pyramid-shaped micro- and nano-structures. The optical band gap of ZnO thin film was estimated to be 3.18 eV. The X-ray diffractometer (XRD) studies re-confirm that the deposited film has a hexagonal wurtzite structure. The study also suggests that there is an intermediate post annealing temperature at which the deposited ZnO film exhibit best surface characteristics. The results of the study can be used as a guideline for growing smooth and homogenous ZnO films, which are suited for electronic/optoelectronic applications. © 2011 American Scientific Publishers.