Effect of plastic deformation on the luminescence of ZnSe crystals

The electronic recombination properties of defects in ZnSe is a subject of interest related to the application of this material in optoelectronic devices operating in the blue-green range. In this work the influence of defects, in particular the deformation induced defects, on the luminescence of bulk ZnSe single crystals has been investigatd by cathodoluminescence in the SEM. The crystals were compressed along [100] direction wih plastic strains of 3% and 6.4% respectively. 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 at 85K shows the near band edge emission at 2.8eV and a broad band peaked at 2.2eV with a shoulder at about 2eV. Deformation at the low strain causes only slight spectral changes while in the heavily deformed crystal a strong relative enhancement of the deep level band in the range 2-2.2eV is observed. The relation of these spectral changes with the deformation induced defects is discussed

Origin of yellow luminescence from reduced pressure grown bulk GaN crystals

Cathodoluminescence (CL) in the scanning electron microscope has been applied to study the luminescence emission of GaN single crystals grown by LPE methods. CL spectra show the presence of near band edge and of yellow emissions. The latter has been found to be mainly related to rows of hillocks formed at the growth steps. The origin of the yellow luminescence is discussed PACS: 78.60Hk; 71.55Eq