Thin amorphous chalcogenide films prepared by pulsed laser deposition

Amorphous Ge-Ga-Se thin films were prepared by pulsed-laser deposition (PLD). using different energy densities of the excimer KrF laser beam (lambda = 248 nm) on the glassy target. The chemical composition of prepared films was close to the composition of the chalcogenide glass targets. The structure of Ge-Ga-Se thin films was studied by Raman spectroscopy; GeSe4/2 tetrahedra, edge-sharing Ge2Se8/2 bi-tetrahedra, some Ge-Ge and Ge-Ga or Ga-Ga as well as Se-Se structural units were revealed. The optical properties (transmittance spectra, spectral dependence of index of refraction, optical gap, single oscillator energy, dispersion energy. dielectric constant) of the films were determined. The relations between the structure, optical parameters and energy density of the laser beam used for PLD are discussed. (C) 2002 Published by Elsevier Science B.V.