The Spectroscopy of localized states in glassy films Ge28.5Pb15S56.5

Ge_28.5Pb₁₅S_56.5 thin films prepared by the flash evaporation technique are under study. The present paper is focused on the investigation of localized defect states in the forbidden band gap of Ge_28.5Pb₁₅S_56.5 which govern transport properties of this material. Thermally stimulated activation spectroscopy methods were used with the view to study localized states in the bandgap of this glassy material. Methods of thermally stimulated conductivity and thermally stimulated depolarization currents were used. Three groups of localized states were examined: a group of shallow ones at 0.2-0.3 eV, located in the band tails; a group with density of states maximum at 0.45 eV (drift mobility in Ge-Pb-S glasses is controlled by this group of localized states); a group found at 0.63 eV (located in the vicinity of the Fermi level). Valuable information about parameters of these localized defect states in Ge_28.5Pb₁₅S_56.5 was obtained.