The properties of ZnSe/(100)GaAs structures were studied. The ZnSe was grown by means of metal-organic vapour-phase epitaxy. Double-crystal X-ray diffraction patterns in the vicinity of the (400) reciprocal lattice points were studied. No macroscopic misorientations of ZnSe with respect to GaAs were detected; thus suggesting the existence of an isotropic defect distribution along the <011> in-plane directions. The generation and propagation of defects due to epilayer strain relaxation produced a mosaic-like structure which led to a characteristic broadening of the double-crystal X-ray diffraction curves. The lineshapes of the patterns were analysed by using a statistical X-ray diffraction theory, and the kinematic approximation, in order to determine the epilayer structure. Simulations of ZnSe/GaAs double-crystal X-ray diffraction curves indicated a mean mosaic block radius of 140 to 150nm and a random mean microscopic misorientation angle, between the blocks, which decreased from 1.3 to 0.4mrad upon increasing the ZnSe thickness from 0.3 to 1.85μm.

Crystalline Structure of ZnSe and ZnSSe Epilayers Grown on (100)GaAs by Metalorganic Vapour-Phase Epitaxy. N.Lovergine, P.Prete, L.Tapfer, A.M.Mancini: Journal of Crystal Growth, 2000, 214-215, 187-91