X-ray diffraction and reflectivity analysis of GaAs/InGaAs free-standing trapezoidal quantum wires

Combined x-ray diffraction and reflectivity experiments have been performed on free-standing trapezoidal GaAs/InGaAs quantum wires using a conventional x-ray tube. Interpreting the intensity distribution around (004) by curve simulation of the extracted coherent grating truncation rods on the basis of a semikinematical diffraction theory (DWBA) the shape and geometric parameters as well as the strain within the wires could be determined taking the results of a finite element calculation of the atomic displacements into account. The map of the coplanar x-ray reflectivity around (000), as well as the intensity profiles of the coherent grating truncation rods, located equidistantly around the specularly reflected beam, have been recorded in order to estimate the roughness properties of the sample interfaces as well as the wire shape and layer set-up without the influence of strain. All small-angle as well as wide-angle scattering experimental results went in to the mutually consistent estimate of the sample properties. The experiments performed for a conventional x-ray tube supply a parameter set comparable in completeness and precision to that obtained from similar samples by interpreting synchrotron experiments.