Influence of Thickness on the Optical Properties of Cadmium Sulphide Thin Film Deposited by Chemical Bath Deposition Technique

Cadmium Sulphide (CdS) thin films were deposited onto glass substrates by chemical bath deposition (CBD) technique from a bath containing Cadmium acetate, ammonium acetate, thiourea and ammonium hydroxide and the bath was maintained at using 78H – 1 hot plate magnetic stirrer. The CdS thin films were deposited simultaneously at different dip times of (10, 20, 30, 40, 50, and 60) minutes to achieve different film thickness of (14.13, 17.61, 18.20, 20.84, 25.93 and 27.21) nm respectively in order to investigate the influence of the thickness on the optical properties of the films. The optical absorbance was measured directly using Single – Beam Helios Omega UV – VIS spectrophotometer in the wavelength range of (280 – 920) nm. Other optical parameters which include; transmittance, reflectance, refractive index, extinction coefficient, and the optical band gap were calculated using the optical absorbance data. Results of the study show that the optical properties of the CdS thin film were largely influenced by the thickness of the films.