A study was made of the dependence of strain relaxation, in epitaxially grown ZnSe/GaAs layers, upon the growth process. New investigations were made of the luminescence signals which were caused by lattice defects in the layers. The strain was attributed to the differing lattice constants of the layer and of the substrate material, and was relaxed by the nucleation of misfit dislocations during growth. This relaxation process depended upon the layer thickness and growth conditions. The residual strain was determined, for various layer thicknesses and growth processes, using X-ray diffractometry. The created misfit dislocations also gave rise to a luminescence at 2.6eV. This was the so-called Y line. It was found that its behavior in ZnSe was analogous to that of the Y lines in epitaxially grown ZnTe/GaAs layers. Excitation of the Y luminescence was possible only for photon energies that were higher than the recombination energy of free excitons. Its intensity decreased with increasing impurity concentration. It also decreased strongly in the case of steady-state excitation at 2K. Recovery of the luminescence intensity was observed when the sample was heated to room temperature.

K.Wolf, S.Jilka, H.Sahin, H.Stanzl, T.Reisinger, A.Naumov, W.Gebhardt: Journal of Crystal Growth, 1995, 152[1-2], 34-41