Structural properties of InAs-based nanostructures grown on GaAs(001) and GaAs(111)A by area selective epitaxy

Area selective epitaxy (ASE) of InAs on patterned SiO2/GaAs(001) and SiO2/GaAs(111)A substrates has been investigated for various In flux intensities and substrate temperatures TS by using migration enhanced epitaxy (MEE). Transmission electron microscopy (TEM) indicates a different behaviour in the strain relaxation mechanism for ASE grown InAs structures on GaAs(001) and those grown on GaAs(111)A. In case of InAs/GaAs(001) Moire-like fringes due to strain relaxation are visible up to at least 35 nm in the InAs dot structure, while for InAs/GaAs(111)A the Moire-like fringes are confined at the interface. Furthermore, electron dispersion spectroscopy (EDS) showed a relatively high In concentration below the interface for InAs/GaAs(001) indicating the formation of a reaction layer even for structures grown at a low TS of 460 C. For InAs on GaAs(111)A grown under the same conditions, almost no In was detected below the interface (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)