Influence of illumination on the microhardness and elastic properties of thin GexSb40-xS60 films

The microhardness of as-deposited and illuminated thin films of GexSb40-xS6 0 glasses has been measured. The volume of the micro-voids, their formation energy and the module of elasticity are determined using the free-volume t heory and are considered in terms of average coordination number Z. The com positional dependences of these quantities show a well expressed peculiarit y around Z = 2.67, indicating the existence of a topological phase transiti on. An increase of the microhardness and the elasticity in the illuminated films is observed as a result of the photoinduced structural changes. (C) 1 999 Elsevier Science S.A. All rights reserved.