Anomalous X-ray scattering study of the local structure in Ge-Se glasses

✍ Scribed by Hosokawa, S. ;Oh, I. ;Sakurai, M. ;Pilgrim, W.-C. ;Boudet, N. ;Bérar, J.-F.

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 1023 KB
• Volume: 206
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200881603

✦ Synopsis

Abstract

Anomalous X‐ray scattering experiments on glassy Ge~x~Se~1−x~ semiconductors have been carried out at energies close to the Ge and Se K edges in a wide concentration range from x = 0.15 to 0.333 across the rigidity percolation threshold composition of x = 0.20. The total structure factors, S(Q), show considerable variation with x in both the position and intensity of the prepeak at about 10 nm^−1^, while in the remaining Q range, it stays almost unchanged. The differential structure factors, Δ~i~S(Q), comprise characteristic features, depending on the absorption edges. Comparing them suggests that the prepeak indicating the existence of intermediate‐range order (IRO) purely originates from the Ge‐Ge partial correlations. In contrast to the S(Q), the prepeak in Δ~Ge~S(Q) changes very slightly with varying x down to x ∼ 0.20, suggesting that the prepeak height in S~GeGe~(Q) largely enhances with decrease in the Ge concentration, in particular at the the rigidity percolation threshold composition. However, a sudden decrease and a shift of the Q position are seen at the Ge concentration less than the stiffness transition composition, which may relate to the sudden decrease of the GeSe~4~–GeSe~4~ connections in the floppy region of this glassy system.