MODELING OF THE SPATIAL STRUCTURE BY MEANS OF WIDE-ANGLE X-RAY-SCATTERING AND EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE FOR THE CU8AS26SE66 AND CU26AS37SE37 SEMICONDUCTOR ALLOYS

Short-range orders of two amorphous alloys of the chalcogenide Cu-As-Se family have been studied by extended x-ray-absorption fine structure (EXAFS) and wide-angle x-ray scattering (WAXS). Up to now, the construction of spatial models by a modified metropolis Monte Carlo simulation technique carried out by us was solely based on the information gained in the WAXS experiments. In this work, we also take into account the information extracted from the spectroscopic EXAFS experiments to get more-realistic spatial models. In this way, the average coordination numbers of the three different atoms and their distances to the first coordination sphere have been determined in Cu8As26Se66 and Cu26As37Se37. The extraction of the inverse Fourier transforms to the generated atomic distribution function leads us to a simulated reduced interference function si(s), in good agreement with its experimental counterpart.