Optical characterization of chalcogenide thin films

In this paper, the optical characterization of a film of amorphous As-S cha lcogenides evaporated on glass substrates will be performed using variable angle of incidence spectroscopic ellipsometry (VASE) and near-normal incide nce spectroscopic reflectometry (NNSR), The spectral dependences of the ell ipsometric parameters and reflectance of the chalcogenide thin film mention ed is measured within the near-UV, visible and near-IR spectral regions, Fo r interpreting these optical quantities the new dispersion model of the spe ctral dependences of the optical constants of amorphous solids is employed. This model is based on the modified Lorentz oscillator. Within this model the concepts of the band gap and Urbach tail are respected. (C) 2001 Elsevi er Science B.V. All rights reserved.