ANOMALOUS BEHAVIOR IN THE COMPOSITION DEPENDENCE OF THE PHOTOACOUSTICPROPERTIES OF SI-AS-TE GLASSES

The optical bandgap and thermal diffusivity of Si10AsxTe90-x (10 less- than-or-equal-to x less-than-or-equal-to 50) and Si15AsxTe85-x (5 less -than-or-equal-to x less-than-or-equal-to 40) glasses have been measur ed using the photoacoustic technique. The anomalous behaviour observed in these properties at the mean coordination number [r] = 2.60 is int erpreted by reference to the formation and development of a layered st ructure in these glasses.