The influence of substrate preparation conditions on the Raman spectra of In2S3 thin films prepared by physical vapor deposition

In this paper, we employed Raman spectroscopy to investigate Indium sulfide thin layer films deposited on glass substrates using the PVD method. The results showed that the bandwidth and Raman shift of different In2S3 thin films depended on the annealing temperature. In addition, the crystallization stage from tetragonal to cubic occurred at the excessive temperature range of 350-400 °C. The Raman spectroscopy of the In2S3 thin films before annealing and at 300 °C indicated the existence of β- In2S3 at 70, 166 and 281 cm^-1 in the active modes of the spectra. New modes that were related to α-In2S3 appeared at 126, 244, and 266 cm^-1 after thermal treatment at 400 °C for 30 and 60 min. Our results are in agreement with the phase transitions observed from the XRD analysis of In2S3 thin films. There are few reports about the Raman spectroscopy of In2S3 thin layer films deposited using vacuum thermal evaporation. In the present paper, the Raman spectra of In2S3 thin films with different thicknesses as well as the effects of temperature on their depositions in vacuum were examined.