Study of Aluminum Doping Effect on Some Optical, Structural and Morphological Characteristics of Nanocrystalline Zinc Oxide Films

Abstract

Undoped and Aluminium (Al) doped ZnO thin films with different weight percentages (0, 2, 4, 6, 8%) were deposited on glass substrates using “sol-gel spin coating method”. Optical, Crystal structural and surface morphological characteristics of all prepared samples have been studied in terms of their doping effects. The crystal structural analysis was done by X-ray diffraction, and the results showed that all prepared films have “polycrystalline hexagonal” type structure with preferred orientation along (002) for all films except for the percentage (4%) where its preferred orientation was (101). The Al doping leads to decrease the crystallite size of ZnO thin films. Other structural properties such as lattice constant, texture coefficient, dislocation density and number of crystalline per unit area for all prepared films have been calculated. (FE-SEM) images results showed that all prepared films were in the range of (10-100nm) scale nanostructure. Also, the values of average grain size decrease and the surfaces became more homogenous with increase of Al doping ratio. The optical results showed that the optical transmittance is >90%, while the optical energy gap increased with increase of Al doping ratio.