COPPER COORDINATION HYPOTHESES AND STRUCTURAL MODEL IN THE GLASSY SEMICONDUCTOR CU0.08GE0.18TE0.74 BY X-RAY-DIFFRACTION

The radial atomic distribution was studied in the amorphous alloy Cu0.08Ge0.18Te0.74, using X-ray diffraction data of samples obtained by quenching the molten material. The short-range order proposed was determined through the interpretation of the radial distribution function, using a theoretical expression which takes into account the variation in the atomic scattering factors with s (scattering vector module) and approximating them to polynomic functions. Different coordination hypotheses for copper, quoted in the literature on glassy alloys containing this element, were taken into account. The result of the study is that tetracoordinated copper is the hypothesis which most agrees with the experimentally obtained structural information. According to this coordination for copper, a spatial atomic distribution model was generated, using the Monte-Carlo random method. A comparative analysis of the main structural parameters of this model revealed its good agreement with the values given in the literature for similar alloys.