Author:
Pietsch U.,Zeimer U.,Hofmann L.,Grenzer J.,Gramlich S.
Abstract
ABSTRACTStrain and compositional modulation in AlxGa1−xAs layers grown by metalorganic vapour phase epitaxy (MOVPE) over a sinusoidally shaped GaAs (001) surface grating were studied by scanning electron microscopy (SEM), X-ray grazing-incidence diffraction (GID) and photoluminescence (PL). Two growth temperatures and two compositions were chosen to realize planar overlayers. By SEM a periodic reduction in Al-content was found at the valley positions of the GaAs grating. The appearance of such vertical quantum wells (VQWs) has been explained by the growth rate anisotropy between high-index and (001) planes and a curvature-induced capillarity flow of Ga. Estimated from PL energies a larger reduction of the Al-concentration in the VQW and also at the high-index sidewall facets was found than compared to predictions from the capillarity flow theory. Using depth-resolved GID we show that the formation of VQWs is accompanied by a periodic lateral strain field. Therefore we assume, that the formation of the VQWs is influenced by strain induced diffusion due to the interaction of opposite sidewall facets.
Publisher
Springer Science and Business Media LLC
Cited by
1 articles.
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