Study of Micrometer-Scale Spatial Variations in Strain of a Compositionally Step-Graded In(x)Ga(1-x)As/GaAs(001) Heterostructure

摘要

The relaxation of strain in compositionally step-graded In(x)Ga(1-x)Al layersgrown on GaAs(O01) has been examined with cathodoluminescence (CL) wavelength and linearly polarized imaging approaches. A polarization anisotropy in CL is found, and this correlates with spectral shifts in the peak positions of excitonic luminescence. Varying asymmetries in misfit dislocation densities from transmission electron microscopy are found to be consistent with the micron-scale spatial variations in strain that is deduced from the CL. (MM).