Localization of Y Luminescence at Glide Dislocations in Cadmium Telluride

Abstract

We demonstrate unambiguously that the well-known defect-related Y luminescence band at 1.476 eV in CdTe originates from the polar Te(g) glide dislocation segments. Crystallographically defined glide dislocation arrangements produced by local plastic deformation on (111)Te surfaces using Vickers microindentation were characterized by temperature-dependent cathodoluminescence (CL) microscopy as well as CL and PL spectroscopy. The identification of the Te(g) dislocation was obtained by determining the surface polarity applying X-ray diffraction and subsequently revealing the volume glide geometry observed by CL imaging after stepwise depth-etching of the (111) sample surface. From the spectral and recombination-kinetic properties of the dislocation-bound Y luminescence the model of radiative decay of dislocation-related excitons is supported. Particularly, we may conclude that they are bound to energy levels in the fundamental gap localized at the 90° Te(g) partial dislocations.