ELLIPSOMETRIC INVESTIGATIONS OF a-As2S3 THIN FILMS OBTAINED BY RF MAGNETRON SPUTTERING

In this paper we report the investigation of optical properties of As2S3 amorphous chalcogenide thin films. Arsenic trisulfide is well known amorphous material. As2S3 thin films have important applications in optoelectronics. The most usual method of fabrication is thermal evaporation in vacuum which is known for deposition ofa-As2S3 films with high probability of oxidation in contact with ambient environment. In this paperwe studied the optical properties of As2S3 thin films obtained by a different method as RF magnetron sputtering. Ellipsometric measurements permit the studies of the film optical constants in high absorption spectral domain which give the possibility to determine the own oscillator frequencies. Fitting model based on the well-established exponential absorption inside the band gap tail and Tauc fundamental absorption was used. Thin films of a-As2S3 comparison were made on Si and glass substrates.