Study of Optical and Structural Properties of SILAR-deposited Cobalt Sulphide Thin Films


  • C. B. Eze Department of Industrial Physics, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Anambra State, Nigeria
  • I. A. Ezenwa Department of Industrial Physics, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Anambra State, Nigeria
  • N. L. Okoli Department of Physics, Legacy University Okija, Anambra State, Nigeria
  • C. I. Elekalachi Department of Industrial Physics, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Anambra State, Nigeria
  • N. A. Okereke Department of Industrial Physics, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Anambra State, Nigeria



Copper sulphide, SILAR method, optical properties, structural properties, bandgap


Cobalt Sulphide (CoS) thin films were deposited on a non-conducting microscopic glass substrates using successive ionic layer adsorption and reaction (SILAR) technique at room temperature. The deposited CoS thin films were subjected to optical and structural characterizations. The absorbance result showed that cobalt sulphide films are moderately absorbing films, with absorbance values ranging from 0.70 to 0.19. Transmittance results show that these deposited films are fairly transparent in visible light and near-infrared regions. Transmittance ranges from 19.8% to 63.9%. The transmittance decreased as the number of SILAR cycles increased. The reflectance of our synthesized films was generally low, with values ranging between 0.10 and 0.20. Our result also shows that within the UV and VIS region, refractive index decreased as the number of SILAR cycles increased for all the films deposited. Refractive index value ranges from 1.92 at 300 nm to its peak value of 2.64 at 1000 nm. The bandgap energy of the films deposited ranged from 2.00 – 2.30 eV. Optical thickness of the films ranges from 0.52 µm to 0.87 µm, which shows an increase as the number of SILAR cycles increased. Structural analysis showed that the XRD pattern of deposited CoS thin films have peaks corresponding to the reflections of hexagonal phase of CoS with lattice parameter a=b=3.377 Å and c=5.150 Å. The preferred orientation is along the [102] plane. Crystallite sizes, microstrain and dislocation density of the films obtained using Williamson–Hall plot method range from 32.25 to 40.78 nm, 2.0×10-4 to 7.0×10-4 and 9.61×1014 to 6.01×1014 lines/m2 respectively.

Author Biography

N. L. Okoli, Department of Physics, Legacy University Okija, Anambra State, Nigeria

*Corresponding Author

Auxiliary affiliation: Department of Industrial Physics, Chukwuemeka Odumegwu Ojukwu University, Uli, Anambra State, Nigeria



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How to Cite

Eze, C. B., Ezenwa, I. A., Okoli, N. L., Elekalachi, C. I., & Okereke, N. A. (2023). Study of Optical and Structural Properties of SILAR-deposited Cobalt Sulphide Thin Films. Journal of Nano and Materials Science Research, 2(1), 123–130.





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