Model of DX-like Impurity Centers in PbTe(Ga).

A new model is proposed for DX-like impurity centers, which are responsible for the Fermi-level stabilization and long-term relaxation effects in IV-VI semiconductors doped with group III elements. The model is based on the idea of a variable valence of the impurity, whereas the nature of the long-term effects at low temperatures is associated with the formation of an effective barrier caused by a change of two units in the impurity valence upon photoexcitation. The model is applied to an analysis of the photoconductivity spectra in PbTe(Ga). The model can also be applied to the classical DX centers in III-V semiconductors. [ABSTRACT FROM AUTHOR]