DefinePK

Abstract

Cupric oxide (CuO) thin films were deposited on the silicon substrate by dip coating technique. The starting material used was copper (II) sulphate pentahydrate (CuSO4.5H2O) which dissolved in de-ionized water and lactic acid while sodium hydroxide (NaOH) was used to control the pH of the solutions. Various pH values of solutions varying from 12.0, 12.3 and 12.5 were optimized in order to determine the optimum condition for dip coating process. The phase structure and morphology of the thin films were investigated by a X-ray diffraction (XRD) and a field emission scanning electron microscope (FESEM), respectively. Meanwhile, the thickness of the films was measured using surface profiler and confirmed with FESEM cross-section. The electrical properties were determined using a four-point probe instrument. The XRD pattern revealed that the deposited films are polycrystalline in nature with monoclinic CuO phase formation. Morphological studies revealed that the individual petals becomes larger, start to become more dense and then formed porous flower-like structure with completely covers over the substrate surface as the pH value increased. The film thickness was 19.6 µm at pH 12.0 which increased to 25.3 µm and 52.4 µm at pH 12.5, respectively. The film showed good resistivity at pH 12.5 with estimated value around 3.8019×103 ?.cm compared to the others. Consequently, it was observed that various pH value has strong effects on the structural, morphological and electrical properties.