Effect of Deposition Time on Material Properties of ZnO Nanorods Grown on GZO Seed Layer by CBD

Abstract

ZnO nanorods (ZNRs) were grown on Ga-doped ZnO (GZO) through a two-step procedure, involving pre-treatment to form the seed layer followed by growth of the nanorods through chemical bath deposition (CBD) method. The study determines the effect of different growth deposition times (ranging between 30 and 150 min) at 90°C growth temperature and 0.05M concentration of precursor solution. The influence of this growth parameter on structural and optical properties of ZNRs thin films is presented. The pattern of X-ray diffraction displayed ZNRs thin films with a polycrystalline hexagonal structure. The estimated crystallite size increased with deposition time while the calculated strain was found to decrease with increase in time, an implication of improved crystallinity at longer deposition time as displayed by highest XRD peak intensity at 90 min. The scanning electron microscopy and atomic force microscopy images exhibited various types of morphologies at different deposition time with homogenously distributed nanorods observed at 90 min. An inverse relation between the optical band gaps and deposition growth time of the prepared nanorods was observed. The ZNRs sample grown on the transparent conductive film of GZO, with high luminescence and perfect crystallization produced at the 90 min growth deposition time could suitable for use as a photoanode component of the dye-sensitized solar cell.