First-principles study of DX centers in CdTe, ZnTe, and CdxZn1-xTe alloys.

Abstract

Large lattice relaxation models for DX centers in CdTe, ZnTe, and ${\mathrm{Cd}}_{\mathit{x}}$${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ Te alloys are examined through first-principles pseudopotential calculations. The calculated binding energies of DX centers for Al, Ga, In, Cl, Br, and I donor impurities in CdTe and their pressure and alloy dependence in ${\mathrm{Cd}}_{\mathit{x}}$${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$Te are in good agreement with experimental data. Three distinct types of DX-like structures characterized by either bond rupture or bond compression are found for column VII donors. The relative stability of these structures is impurity and pressure dependent.