EVIDENCE OF DISTINCT STRUCTURAL CLUSTERS IN AMORPHOUS GE1-XSNXSE2

The structure of amorphous Ge1-xSnxSe2 has been examined at liquid nitrogen temperatures (atmospheric pressure) and at high pressures (room temperature) using Mossbauer spectroscopy. The low temperature study shows that the fraction of Sn atoms occurring in a tetrahedrally bonded site does not change with concentration, remaining at 0.85 for 0.20 less-than-or-equal-to x less-than-or-equal-to 0.60. The measurements at high pressure were made on a glass with composition Ge0.5Sn0.5Se2. The data are consistent with a hypothesis that the glasses are made up of distinct structural clusters. Two different regions of response to pressure were interpreted as a low pressure region in which the intercluster interactions were changed and a high pressure region in which the intracluster interations were affected.