Glass formation and vibrational properties in the (Ge, Sn) system

Abstract

The glass forming tendency and infrared reflectance spectra are investigated in the (Ge, Sn) system. It is found that the glass formation of the SnSe system is much more difficult than that of the Ge system. This is mainly ascribed to the ionicity difference between GeSe and SnSe bonds. Infrared spectra in the glassy Ge 1- x Se x system at the composition 0.67< x<1.0 indicate the presence of clusters within which the atomic connectivity is similar as in the glassy GeSe 2. The vibrational modes caused by the SnSe 4 2 tetrahedron are found in the glassy (Ge, Sn)-Se system. It is suggested that tin atoms are mainly incorporated into the clusters. Importance of the medium range order is discussed in the formation of the glasses.