Dynamical x-ray rocking curve simulations of non-uniform InGaAs and InGaAsP using Abeles matrix method.

Computer simulations of the intrinsic (400) reflecting power of In(1-x)Ga(x)As layers having graded compositions are presented. We find the multiple x-ray peaks can result from a linearly graded region which implies that an interpretation which ascribes individual peaks to sublayers having a constant lattice parameter may not always be correct. We find that, in general, the simulations are asymmetric and that they have FWHM less than ~100 arcsec. We have simulated a rocking curve of a single In(1-x) Ga(x)As (1-y)Py layer grown on a (100) InP substrate which exhibited multiple peaks, and we find that a good fit is possible if the layer has a graded lattice parameter.