Raman scattering and X-ray diffraction studies of Ge16Sb24Se60 alloys

The structure and vibrational properties of glassy Ge16Sb24Se60 alloys were studied using X-ray diffraction and Raman scattering. The experimental X-ray diffraction patterns confirmed the amorphous nature of the obtained alloys. The latter were used for calculating the radial distribution functions. These calculations gave the positions of the nearest-neighbour peak r1 – 2.56 A and the second nearest-neighbour peak r2 – 3.79 A. The obtained r1 value aligns well with the known Ge-Se and Sb-Se bond lengths from the literature. Similar r1 value was also observed for Ge-Sb-Se glasses of different compositions. The r2/r1 ratio of 1.48 yields the value of the bond angle ? = 95.5°. The observed bands in the Raman spectra of the studied Ge16Sb24Se60 samples show that these glasses contain different nanophases. The Raman spectra can be interpreted in terms of vibrational modes of Ge-Se and Sb-Se binary glasses and films.