Electrical and Optical Characteristics of Copper Antimony Sulphide Thin Films Fabricated in Chemical Baths of Different Growth Media

Abstract

Chemical Bath Deposition Technique has been used to fabricate thin films of copper antimony sulphide in two different growth media: water and polyvinyl alcohol and the effects of these media on the electrical and optical properties of the CuSbS 2 thin films studied. The technique required a liquid precursor; usually a solution of organic metallic powder dissolved in an organic solvent and kept in a reaction bath where reaction takes place. The precursor reaction chemicals used were copper chloride, antimony chloride and sodium thiosulphate and precipitations were on pre-cleaned borosilicate glass substrate at room temperature and pH of 9.1. Both deposits were subsequently similarly annealed for an hour each at a temperature of 250°C before testing the optical characteristics of both films using a UV-VIS-NIR 200-1100 nm range spectrophotometer and electrical characteristics, using a Quadpro four point probe. A proton induced Rutherford backscattering done on films detected thicknesses of films to be 545 nm and 514 nm for water and PVA bath deposits respectively. The thin film resistivities recorded were also 770 Ωm and 699 Ωm respectively. Absorbance, refractive indices, and other major optical parameters of the thin films varied differently with growth media in the infra red but remained fairly same in the visible and other higher frequency ranges.