STUDY THE EFFECT OF THICKNESS ON THE OPTICAL PROPERTIES OF (Sb2O3) THIN FILMS PREPERD BY THERMAL EVAPORATION TECHNIQUE

Antimony trioxide (Sb2O3) Thin films with different thickness t=200, 300 and 400 nm were deposited onto glass substrates by thermal evaporation technique. The effect of film thickness on optical properties was investigated. The spectral absorption coefficient and optical band gap energy of thin films at the fundamental absorption region were determined using the spectral data of transmittance measurements in the wavelength range 300- 900 nm. It was found that the transmittance (T), absorbance (A) and optical band gap, Eg , depend markedly on the films thickness. The optical band gap decreases from 3.30 to 3.25 eV when the films thickness increase from 200 nm to 400 nm .The transmission spectrum corresponding of thinner film (t = 200 nm) demonstrates that the film was highly transparent (transmittance approaches 93%) in the visible and near infrared regions. The transmittance of the thicker film (400 nm) is decreases to 76 %.