Investigation of Physical Properties of PbS Thin Films Containing Surfactant in Different Ratios

Abstract

In the present study, polycrystalline lead sulfide thin films have been successfully deposited on glass substrates using chemical bath deposition technique in the presence of cocamide diethanolamine. The effects of cocamide diethanolamine used in different ratios on the structural, morphological, and optical properties of PbS thin films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning probe microscopy (SPM) and UV-visible spectroscopy analyses. From the XRD analysis, it was obtained that the crystal size of the PbS thin films decreased from 12.57 nm to 5.43 nm with the increase in the amount of cocamide diethanolamine additive. In addition, the microstrain and dislocation density values increased depending on the amount of cocamide diethanolamine additive. SEM analysis shows that cocamide diethanolamine additive affects the surface morphology of nanostructured PbS thin films. SPM analysis showed that the surface roughness values of the thin films increased with the increase of cocamide diethanolamine additive. By UV-visible spectroscopy analysis, it was obtained that the optical transmittance value of the PbS thin film increased approximately 3 times at the amount of 1% cocamide diethanolamine additive. In addition, the optical band gap values of PbS thin films increased from 1.87 eV to 2.53 eV depending on the amount of cocamide diethanolamine.