A structural study of liquid Te-rich Si-Te alloys

X-ray diffraction measurements using synchrotron radiation on liquid Si_xTe_1−x (x≥0.2) were carried out at several temperatures. At constant temperature, the first peak, which is composed of Si-Te and Te-Te correlations, of the pair distribution function gradually shifts to the shorter distances with increasing Si content. These shifts indicate the substitution of Si-Te bond for the Te-Te bonds in the first peak. The total coordination number shows little temperature variation and remains about two in the temperature interval of a few hundreds of degrees. The composition and temperature behaviour of the Te-rich side of Si-Te liquid alloys has already been investigated, among which thermodynamic behaviour is a quite contrast to that of the Ge-Te alloys in the overlapping composition-temperature range of the present investigation. We clarify the evolution of the local structure of the liquid Si-Te alloys in comparison with the liquid Ge-Te alloys.