Low-temperature ZnSe photoluminescence spectra with very narrow bound exciton line-widths (0.55meV) were presented. This demonstrated, for the first time, that thin pseudomorphic ZnSe layers with minimal inhomogeneous strain could be grown directly onto GaAs by means of molecular beam epitaxy. A similar characterization of ZnSe/AlAs/GaAs heterostructures showed that AlAs layers which were up to 0.004mm in thickness exhibited only kinetically limited partial lattice relaxation. This prevented the overgrowth of uniform coherently-strained ZnSe layers. However, pseudomorphic ZnSe/AlAs/GaAs structures with thin (less than 0.0005mm) AlAs layers exhibited the narrowest bound exciton peaks (less than 0.37meV full-width at half-maximum) which had ever been reported for hetero-epitaxial ZnSe. This reflected a high degree of structural perfection.

B.J.Skromme, M.C.Tamargo, J.L.De Miguel, R.E.Nahory: Applied Physics Letters, 1988, 53[22], 2217-9