Deformation-induced defect levels in ZeSe crystals

Abstract

The influence of defects, in particular the deformation-induced defects, on the luminescence of bulk ZnSe single crystals has been investigated by cathodoluminescence (CL) in the scanning electron microscope. Deformation has been found to cause a reduction of the total CL intensity of the sample. CL images of deformed samples reveal dark slip bands. The CL spectrum of an undeformed crystal shows the near-band-edge emission at 2.8 eV and a broad band peaked at 2.2 eV with a shoulder at about 2 eV. Deformation at low strain causes only slight spectral changes while in a heavily deformed crystal a strong relative enhancement of the deep level band in the range 2-2.2 eV is observed. The relation of these spectral changes to the deformation-induced defects is discussed. The infrared spectra show the existence of broad bands at 0.95 and 1.27 eV. However, these emissions were found to be rather insensitive to deformation.