TRANSMISSION ELECTRON-MICROSCOPY AND CATHODOLUMINESCENCE OF TENSILE-STRAINED GAXIN1-XP INP HETEROSTRUCTURES .2. ON THE ORIGIN OF LUMINESCENCE HETEROGENEITIES IN TENSILE-STRESS RELAXED GAXIN1-XP/INP HETEROSTRUCTURES/

We have determined the origin of the spatial luminescence fluctuations observed between the dark line defects present in tensile strained Ga xIn1-xP/In1-xP/n(+)-InP heterostructures (Part I [F. Cleton et al. J. Appl. Phys. 80, 827 (1996)]). For that purpose, we have undertaken sem i-quantitative and spectroscopic cathodoluminescence (CL) measurements on various specimens in areas exhibiting CL contrasts which could be as large as 80%. The analysis of the variation of the CL polychromatic signal with electron beam energy allowed us to get information on the diffusion-recombination (DR) parameters of the areas under study. Fro m the correlation between the local relaxation level of these areas an d their DR parameters, we can conclude that the variation of the misfi t dislocations density at the GaxIn1-xP/InP interface is at the origin of the luminescence heterogeneities. We also demonstrate that recycli ng, by the GaxIn1-xP epilayer, of the photons originating from the hea vily doped InP substrate, enhances the CL contrast between areas exhib iting different relaxation levels. (C) 1996 American Institute of Phys ics.