Artículos de revistas
EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE INVESTIGATION OF SHORT-RANGE ORDER IN A-GE1-XSNX ALLOYS
Registro en:
Physical Review B. American Physical Soc, v. 46, n. 11, n. 6718, n. 6723, 1992.
0163-1829
WOS:A1992JN82600006
10.1103/PhysRevB.46.6718
Autor
PASCARELLI, S
BOSCHERINI, F
MOBILIO, S
ZANATTA, AR
MARQUES, FC
CHAMBOULEYRON, I
Institución
Resumen
The local environments of germanium and tin atoms in a-Ge1-xSnx alloys (0.0 less-than-or-equal-to x less-than-or-equal-to 0.2) have been investigated by measuring the extended x-ray-absorption fine structure (EXAFS) at the Ge K edge and at the Sn L(III) edge. The measured EXAFS at both edges could be described only by assuming the presence of a mixed first coordination shell composed of both Ge and Sn atoms. Coordination numbers, bond lengths, and relative mean-square displacement values characterizing the first coordination shell around Ge and Sn atoms were obtained. It has been found that the Sn atoms are randomly distributed in the amorphous Ge network, and that metallic Sn segregation may be excluded throughout the concentration range studied. The Ge-Ge, Ge-Sn, and Sn-Sn distances were found to be independent of concentration and equal to 2.47, 2.67, and 2.80 angstrom, respectively. The random atomic arrangement observed is an indication that, in this concentration range and under the growth conditions adopted, the incorporation of Sn in the amorphous Ge matrix is dominated by chemical interactions, regardless of the atomic-size difference between the two atoms. 46 11 6718 6723