Effect of organic solvents on zinc oxide chemical and structural properties

Sol-gel method is a high yield, low cost, simple technique, and robust technology that we frequently use in our laboratory. Solvents are crucial components in specialty chemical processes, and have a significant influence on the properties of thin film materials. In this paper, a series of three spin-coated zinc oxide thin films were prepared and characterized to compare the effect of different solvents such as 2-methoxyethanol, ethanol and isopropyl alcohol (IPA) on the morphological, structural and chemical properties of coated films. To this purpose, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) techniques were used. According to the results of XRD data, the presence of crystallography plane (002) wurtzite phase was revealed in all the synthesized films. The crystallite average sizes, estimated by means of Scherer formula, ranged between 28 and 43 nm as function of the nature of solvents. SEM analysis indicated that the samples exhibited dense particle morphology with grains well-ordered and EDS spectra showed Zn and O elements. The crystal qualities, grain size, diameter, d-spacing and texture coefficient of the as-grown films were affected by the type of solvent used in the ZnO layer preparation. These results suggest that it is possible to vary the chemical and structural properties of coated zinc oxide thin films by controlling the organic solvents. As 2-methoxyethanol, ethanol and IPA were used to prepare the ZnO films, highly (002)-oriented ZnO thin films were formed with 2-methoxyethanol.