Bond lengths and lattice structure of lnP_(0.52)Sb_(0.48) grown on GaAs

摘要

We performed reciprocal space mapping (RSM) and extended x-ray absorption fine structure (EXAFS) measurements to investigate the lattice structure of InP_(0.52)Sb_(0.48) grown on GaAs. The RSM data reveal the existence of residual strain in the 1-μm-thick epilayer. The average vertical to horizontal lattice constant ratio, a_z/a_(xy), is 1.009. We used a valence force field model to calculate the distortion energy and bond lengths of InPSb supercells with different a_z/a_(xy) ratio. The calculated InP and InSb bond lengths are in good agreement with the results of EXAFS. Both bond lengths are close to those in corresponding end-point binaries. We attributed the residual strain to the non-vanishing distortion energy resulting from the bond length mismatch between InP and InSb bonds.