Studies on Structural, Surface Morphological, Optical, Luminescence and UV Photodetection Properties of Sol Gel Oxides Thin Films

Abstract

ZnO and ZnCoO thin films have been deposited onto glass substrates by sol-gel spin coating method. Zinc acetate dihydrate, cobalt acetate tetrahydrate, Isopropanol and monoethanolamine (MEA) were used as a precursor, doping source, solvent and stabilizer respectively. The molar ratio of MEA to ions metal was maintained at 1.0 and a concentration of metal ions is 0.6 mol.L -1 .The XRD results showed that both films crystallized under hexagonal wurtzite structure and presented a preferential orientation along the c-axis with the maximum crystallite size was found is 25nm. Atomic force microscope (AFM) images revealed the good uniformity for both films, an increase of surface roughness is observed with doping. The average transmittance in the visible region was higher than 85% for both films and the optical band gap of Zinc oxide films decreased with Co doping. Photoluminescence of the films showed a ultraviolet (UV) and defect related visible emissions like violet, blue and green, and indicated that cobalt doping resulted in red shifting of UV emission and the reduction in the UV and visible emissions intensity. Ours thin films shows the best photocurrent properties.