Glancing-angle extended x-ray absorption fine structure study of strained InGaAs/GaAs heterostructures

The structural properties of strained InGaAs grown by molecular beam epitaxy on GaAs(100) substrates, have been studied by glancing-angle extended x-ray absorption fine structure (EXAFS). The very low incidence angle of the x-ray beam on the sample makes it possible to collect the signal coming from a thin quasi-surface layer allowing the study of a single strained sample built up by only 6 ML of InGaAs. The EXAFS results show that a slight deformation of the first shell Ga--As distance occurs and that the strain is accommodated also by bond-bending mechanism as deduced by the second and third coordination shells analysis. The lattice expands in the growth direction in agreement within the limits predicted by the elastic theory. copyright 1995 American Institute of Physics