Local structures of single-phase and two-phase GaAs1−x Sb x studied by fluorescence-detected EXAFS

Local structures of a single-phase GaAs_0.5Sb_0.5 alloy grown on InP by MBE and two-phase GaAs_1−xSb_x alloys grown from melt were studied by fluorescence-detected EXAFS. We found that in the single-phase GaAs_0.5Sb_0.5, the Ga-As bond is stretched from 2.447Å in pure GaAs to 2.469Å and the Ga-Sb bond is contracted from 2.640Å in pure GaSb to 2.619Å. In the phase separated GaAs_1−xSb_x, the bond lengths were the same as the values in pure binary compounds. These results indicate that, under the lattice-matching constraint, the single-phase GaAs_0.5Sb_0.5 is stabilized with the bond length relaxation.