Short-Range Order in Se-Rich Ge–Se Glasses—An Extended X-Ray Absorption Fine Structure Study

Intermediate-range order in glassy GexSe1−x around the stiffness transition composition

“…Therefore, precise studies of the concentration dependence of the atomic structure of glassy Ge x Se 1Àx were performed using this technique in the concentration range 0 6 x 6 0:333 [11][12][13]. The experiments confirmed the predicted coordination numbers (8 À N rule) with a bond length similar to that in the crystal.…”

Structure modeling for covalently bonded network glasses

“…Well-resolved first and second peaks are found at around 2.36 Å and 3.90 Å , which provide information about the first and second coordination spheres. A shoulder at the left side of the second coordination peak, centered around 3.1 Å , is clearly seen in both g N (r) and g X (r); this is assigned to the signal of edge-sharing GeSe 4 tetrahedral units [7,8].…”

“…Although many kinds of structural studies for the prototypical network Ge-Se glasses have been performed to investigate their microscopic structure of the system [1][2][3][4][5][6][7][8][9][10][11], the glass network structure of these alloys is not yet fully understood.…”

Reverse Monte Carlo simulations and Raman scattering of an amorphous GeSe4 alloy produced by mechanical alloying

“…1). The broad and intense band at 255 cm −1 is related to A 1 and E 2 modes of Se n rings 8,10,44,45,46 . It is important to note that the band at around 165 cm −1 , which is associated with Ge-Ge pairs vibrations in ethanlike units, is not seen in the spectrum of the alloy (as well as the other bands of c-Ge), indicating that the quantity of Ge-Ge pairs is very low in the alloy.…”

“…One of them is the difficulty in obtaining information about atomic structures, which define the short-range order (SRO) of the alloy. In this context, the structures of amorphous Ge x Se 1−x (a-Ge x Se 1−x ) and liquid Ge x Se 1−x (l-Ge x Se 1−x ), in particular Ge 33 Se 67 (GeSe 2 ), have been extensively studied by several experimental techniques, like neutron diffraction (ND) 1,2,3,4,5 , x-ray diffraction (XRD) 6,7 , extended x-ray absorption fine structure (EXAFS) 8,9 and Raman spectroscopy (RS) 10,11,12 . On the theoretical side, molecular dynamics simulations (MD) 13,14,15,16,17,18,19,20,21 and reverse Monte Carlo (RMC) simulations 7 have been carried out to understand the SRO in these liquids and glasses in terms of two possible and distinct models.…”