Fatigue and temperature dependence of photoluminescence in some GexSe1−x glasses

Photoluminescence (PL) intensity versus temperature curves in the x = 0.16, 0.20, 0.25 glasses reveal localized states at ∼0.1 and 0.5 eV from the conduction band edge; these states are attributable to the Se component. The PL intensity increases and fatigue rate decreases with the atomic fraction of Ge in the composition range x < 0.33. Fatigued samples resensitize to some extent if kept in darkness. These observations can be explained by, and support, a structural model of planar oligomers composed of Ge(Se12)4 tetrahedra embedded in Se matrix.