Influence of sodium dodecyl sulfate as a surfactant on the microstructural, morphological and optoelectronic characteristics of SILAR deposited CuO thin films

Abstract

The research was performed aiming to evaluate the impact of sodium dodecyl sulfate (SDS) as a surfactant on the morphological, microstructural, electrical and optical features of nanostructured cupric oxide (CuO) thin films. CuO thin films were grown using successive ionic layer adsorption and reaction (SILAR) technique at room temperature. These as-prepared CuO thin films were thoroughly characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), four-point probe method, UV-Visible spectrophotometer and Fourier transform infrared (FTIR). Surface morphology investigations revealed the uniform and homogeneously distributed CuO nanostructures on the film surfaces. The addition of different concentration of SDS to the growth solution significantly influenced the surface morphological characteristics of the CuO thin films. XRD analysis showed that all deposited CuO thin films were polycrystalline nature having monoclinic crystal system and presented () and (111) preferential orientations. The microstructural parameters, including crystallite size, texture coefficient, microstrain and dislocation density were extracted from XRD data. The resistivity value of CuO thin film prepared without SDS was 1.72 × 106 Ω cm. With SDS concentration of 4.0 M%, the resistivity extraordinarily increased to 3400 × 106 Ω cm. The optical bandgap energy had increased from 1.32 to 1.49 eV as a function of increasing SDS concentration. The CuO bond vibration was confirmed by FTIR analysis.