Optical Properties of Radio Frequency- Sputtered CdSe Thin Films for Photoelectric Applications

Nanocrystalline Cadmium Selenide (CdSe) films were deposited on glass substrates by Radio frequency sputtering technique with different power of argon plasma. The influence of acquired thickness of sputtered films on optical characteristics was investigated. The influence of preparation conditions on thin film thickness was identified, is highly influenced by the argon discharge plasma’s sputtering power. UV-Visible transmittance spectra indicated the optical characteristics, and the bandgap energy was calculated. The films were discovered to have a direct allowed transition after optical absorption investigations. The direct bandgap energy was found to decrease as sputtering power increases along with film thickness. The slight decrease has been attributed to the increasing diffusion impurities which occupy interstitial sites between selenium atoms. The dielectric constants, extinction coefficient, and refractive index generally increased with increase in films thickness due to increased density of the deposited films as a result of sputtering power increasing. The results showed good optical properties of the films deposited at 100 °C using the RF sputtering technique which is suitable to use as an active layer in thin-film-based photoelectric cells.