BOND-LENGTH VARIATION IN INXGA1-XAS INP STRAINED EPITAXIAL LAYERS/

Tensile and compressive InxGa1-xAs epilayers gram on [001] InP substra tes have been analyzed by fluorescence-detected x-ray-absorption. fine structure in order to investigate the length variation suffered by Ga -As and In-As atomic bonds under epitaxial strain. A morphological and structural analysis-had previously been performed in order to select only pseudomorphic samples with high lattice quality. A clear variatio n of the nearest-neighbor distances proportional to the tetragonal dis tortion of the film has been detected. We discuss the relationship bet ween the long- and short-range descriptions of strain accommodation in the framework of an analytical model.