Optical properties of new chalcogenide glasses from the GeSe2–Sb2Se3–PbSe system

Optical properties of thin films in the GeSe2–Sb2Se3–PbSe system are studied as a function of the PbSe content and at different ratio GeSe2/Sb2Se3. Transmission spectra of thin films are investigated. From the above spectra the absorption coefficient α for different PbSe content are derived. The increase of the absorption coefficient α is attributed to the increase of the current carriers density in the valence band.Optical band gap of the samples is determined using Tauc’s procedure. A correlation between the optical band gap and the composition of these chalcogenide samples could be seen. This might result from the increasingly stronger metal character of the bond that leads to the formation of a complicated band gap structure.