Room Temperature Synthesis of Zinc Zno and Azo Thin Films by Successive Ionic Layer Adsorption and Reaction Method and Its Structural and Optical Characterization

Abstract

ZnO and Al-doped ZnO (AZO) thin films were grown by Successive Ionic Layer Adsorption and Reaction (SILAR) method on a glass substrate from sodium zincate solution. Doping was achieved with controlled introduction of aluminum chloride. The technique involved multiple dipping of the substrate in an aqueous solution of sodium zincate kept at room temperature and a hot water bath kept at 95 o C in which ZnO and AZO thin films were synthesized at 0.125M and 0.25M of sodium zincate (Na2ZnO2) where 100 and 200 dippings were performed for each. The thickness of the layers were determined using Metler PB303 digital balance and a Radicon 10 mini- diffractometer (XRD) for the structural characterization while optical characterization was achieved with the use of a Jenway 6405 UV-Vis Spectrophotometer. The results revealed (002) peaks for ZnO thin films and (112) peaks for AZO thin films. Also the transmittances of the ZnO films were higher than those of AZO while AZO films have higher absorbance than those of ZnO films. The energy band gap of both ZnO and AZO were both found to be between 3.71eV and 3.80eV, the values which are slightly higher than most reported values in literature. Keywords - Absorbance, AZO, Energy bandgap, SILAR, Thin Films, XRD, ZnO