J. Phys. IV France 7 (1997) C2-543-C2-544
Dynamical Bonds in the Photoexcited State of Amorphous Selenium Observed by In-Situ EXAFSA.V. Kolobov1, 2, H. Oyanagi3 and K. Tanaka1
1 Joint Research Center for Atom Technology, National Institute for Advanced Interdisciplinary Research, 1-1-4 Higashi Tsuluba, Ibaraki 305, Japan
2 On leave from A.F. Ioffe Physical-Technical Institute, Russia
3 Electrotechnical Laboratory, 1-1-4 Umezono, Tsukuba, Ibaraki 305, Japan
Photostmctural change in amorphous selenium measured by high-precision in-situ EXAFS reveals a reversible increase in the coordination number in the photoexcited state due to the formation of interchain bonds which are formed by excited lone-pair electrons. These extra bonds, formed in concentration of up to 10%, are dynamical and break after switching off the light resulting in a change of the chain topology. We demonstrate that this mechanism of the photostructural change is also valid for compound chalcogenide glasses.
© EDP Sciences 1997