Atomic structure of the (2 x 4) In0.53Ga0.47As/InP(001) reconstructed surface. A study of average strain and growth temperature effects on the indiumsegregation

The influence of the average strain and the growth temperature on the surfa ce structure of ternary alloys has been studied by depositing in situ latti ce matched In0.53Ga0.47As on an InP(001)substrate by molecular beam epitaxy . Under As-rich cooling conditions, a (2 x 4) reconstruction has been obser ved, where a specific ordering of cation within the last (In, Ga) plane has been evidenced by in situ grazing incidence X-ray diffraction measurements . In contrast with the case of strained InxGa1-xAs layers deposited on GaAs substrates, no tendency for indium surface segregation has been detected i n the top cation layer. The atomic positions in the (2 x 4) surface unit ce ll are fully determined. (C) 1999 Elsevier Science B.V. All rights reserved .