Study of microstructure of amorphous Ge-Se films using spectroscopic ellipsometry

Abstract

The dielectric function spectra ε^~ = ε₁-iε₂ of evaporated amorphous Ge-Se films in the energy range 2-5.2 eV have been studied using spectroscopic ellipsometry (SE). The ε̃ spectra of Ge_xSe_{1 - x} (0.2 ≤ x ≤ 0.33) films exhibit a two-peak behaviour showing the presence of a well-separated lone-pair band on top of the valence band. The effect of composition, angle of deposition and photoexposure have been studied. Detailed analyses of SE data have been carried out to yield quantitative information on the microstructure of the films.