Observation of stress effects on GaAs at the interface of molecular beam epitaxy grown ZnSerGaAs 100/heterostructures

We report the observation of stress effects on GaAs at the interface of molecular beam epitaxy grown MBE. ZnSerGaAs. These effects were observed for samples with ZnSe epilayers thicker than their critical thickness 0.17 mm through the application of photoreflectance PR.and reflectance difference RD.spectroscopy. Comparison between the first derivative of the RD spectra DRD.and the PR spectra indicates that in a sample 0.1 mm thick, the PR is a normal bulk-like GaAs signal. The same comparison indicates that for samples thicker than the critical thickness, there are two components in the PR spectra: a bulk-like signal as for the thin sample, and a second signal coming from a strained region populated by dislocations. From the theory of PR spectra, we estimate that the observed strain is «s0.0010"0.0004 in the GaAs at the heterostructure interface with a ZnSe layer 1.05 mm in thickness. q1998 Elsevier Science B.V. All rights reserved.