Effect of grain size and strain on the bandgap of glancing angle deposited AZO nanostructures

Vertical and tilted nanorod arrays of Al-doped ZnO were deposited by glancing angle deposition method at room temperature. The morphologies of the samples were varied by adjusting the rotation speed of the substrate. The applicability of various analytical methods was considered in order to understand the structural results. Analysis of X-ray diffraction data showed that the most suitable evaluation of some structural parameters was performed with a 'strain profile' model. The values of the grain size and strain obtained from the best fits of this model to the experimental data were reasonable. The bandgap increased with decreasing grain size and increasing strain for the samples. The change in bandgap of the samples was explained by our detailed structural analysis.