Quantum Confinement effects on the Band Gap of Bi 2S3 Thin Films using Chemical Bath Deposition

Chemical bath deposition technique has been used to prepare Bi 2S3 thin films for various applications. Optical absorption studies were carried out using UV-VIS-NIR Spectrophotometer (Model-V-570) in the wavelength range 190 nm to 2500 nm at room temperature. Transmittance spectra of Bi 2S3 thin films increases monotonically with the increase in wavelength; but decreases monotonically with the increase in film thickness. Optical band gap energy was decreased with increase in thickness.