Extended x-ray absorption fine-structure measurement of bond-length strain in epitaxial Gd2O3 on GaAs(001)

Extended x-ray absorption fine structure (EXAFS) has been used to measure the bond length in a 23 Angstrom epitaxial Gd2O3 film grown on GaAs(001). The Gd-O bond length is determined to be 2.390 +/- 0.013 Angstrom, which corresponds to a +0.063 +/- 0.013 Angstrom increase or a +2.7%+/- 0.6% bond-length strain relative to the bond length in a bulk Gd2O3 powder. Using a simple model for the strained film that matches the {[}001] and {[}-110] axes of Gd2O3 with the {[}110] and {[}1-10] axes of the GaAs(001) surface, the measured bond-length increase of the film determined by EXAFS agrees well with the perpendicular lattice distortion of the film determined by diffraction. (C) 2000 American Institute of Physics. {[}S0003-6951(00)00618-5].