Nickel Antimony Sulphide Thin Films for Solar Cell Application: Study of Optical Constants

Abstract

Chemical bath deposition technique has been used to deposit Ni-doped Sb2S3 thin films onto glass substrate. Doping was carried out by adding 1, 3 and 5 wt% of Ni. Bath temperature was kept as 10℃ and films were annealed at 250 ℃ under vacuum. Polycrystalline nature of films with an orthorhombic phase was analyzed by X-ray diffraction technique. Scanning electron microscopy was used for morphological study which shows that grains are spherical. Optical measurements using transmittance data indicated that films have a direct band gap of 1.00 - 2.60 eV with an absorption coefficient of ~104 cm - 1 in visible range. The average value of electrical conductivity was calculated as 1.66, 1.11 and 1.06 (Ω · cm) -1 for as-deposited films and 1.90, 2.08 and 1.15 (Ω · cm) - 1 for annealed films while refractive indices were found as 2.18 - 3.38 and 1.91 - 3.74 respectively. The obtained films can be used for solar cell applications due to their good absorbing properties like higher absorption coefficient and refractive index values.