Studies of short-range ordering in amorphous In-Se films by EXAFS

Amorphous In-Se films, containing 50, 60 and 66 at./o Se, prepared by vacuum evaporation, have been studied by extended absorption fine structure at the Se K-edge. A least-squares fitting procedure has been applied to analyse the measured spectra. The results indicate that for the In49Se51 amorphous film an In-Se contribution with the interatomic distance of 2.63 Angstrom and a threefold coordination of Se is involved in the nearest-neighbour coordination sphere. As the Se content is increased, the number of Se-In bonds is reduced and Se-Se bonds occur. preserving the total coordination number of Se. The relationship between the short-range order in the investigated films and the local atomic arrangements in corresponding crystalline polymorphs is discussed. (C) 2002 Published by Elsevier Science B.V.