COMBINED TRANSMISSION ELECTRON-MICROSCOPY AND CATHODOLUMINESCENCE STUDIES OF DEGRADATION IN ELECTRON-BEAM-PUMPED ZN1-XCDXSE ZNSE BLUE-GREENLASERS/

We explored degradation in electron-beam-pumped Zn1-xCdxSe/ZnSe laser structures by combining cathodoluminescence (CL) measurements in a sca nning electron microscope with transmission electron microscopy. The r ate of degradation, measured as the decrease of the emitted CL intensi ty under electron bombardment, depends critically on the threading dis location density and on the strain in the quantum well. Degradation oc curs via the formation of dark spot defects, which are related to bomb ardment-induced networks of dislocation loops in the quantum well. The se degradation defects often initiate where threading dislocations cro ss the quantum well. We propose a self-supporting dislocation climb me chanism activated by nonradiative recombination to explain the formati on and propagation of the degradation defects. (C) 1998 American Insti tute of Physics.