SURFACE ALLOYING AT INAS-GAAS INTERFACES GROWN ON (001)-SURFACES BY MOLECULAR-BEAM EPITAXY

In situ scanning tunnelling microscopy and reflection high energy elec tron diffraction have been used to study InAs-GaAs interfaces grown on (001) surfaces by molecular beam epitaxy. For the deposition of InAs on GaAs(001) a number of different surface reconstructions can be iden tified, depending on substrate temperature and InAs coverage, and ther e is significant evidence for alloying in the surface layer. An (In,Ga )As wetting layer is formed and the complete range of surface reconstr uctions are discussed, together with the tendency of indium atoms to s egregate following the deposition of a further GaAs capping layer and the formation of GaAs-InAs-GaAs(001) interfaces. Finally, a comparison is made with the surface structure of GaAs layers deposited on InAs(0 01) substrates. (C) 1997 Elsevier Science B.V.