Local structure of InxGa1-xAs semiconductor alloys by high-energy synchrotron x-ray diffraction -: art. no. 205202

Nearest- and higher-neighbor distances as well as bond length distributions (static and thermal) of the InxGa1-xAs (0 less than or equal tox less than or equal to1) semiconductor alloys have been obtained from high-real-space resolution atomic pair distribution functions. Using this structural information, we modeled the local atomic displacements in InxGa1-xAs alloys. From a supercell model based on the Kirkwood potential, we obtained three-dimensional As and (In,Ga) ensemble average probability distributions. These clearly show that As atom displacements are highly directional and can be represented as a combination of < 100 > and < 111 > displacements. Examination of the Kirkwood model indicates that the standard deviation (sigma) of the static disorder on the (In,Ga) sublattice is around 60% of the value on the As sublattice and the (In,Ga) atomic displacements are much more isotropic than those on the As sublattice. The single-crystal diffuse scattering calculated from the Kirkwood model shows that atomic displacements are most strongly correlated along < 110 > directions.