On elastic relaxation and long wavelength microstructures in spinodally decomposed In(x)Ga(1-x)As(y)P(1-y) epitaxial layers.

The orgin of the long wavelength (100 to 300 nm) quasi-periodic microstructure observed in transmission electron microscopy studies of spinodally decomposed In(x)Ga(1-x)As(y)P(1-y) alloys has been investigated. The contrast is well explained by diffraction effects arising from lattice plane bending near the surfaces of the thinned specimens, such as would be induced by elastic relaxation of shear stresses accompanying a quasi- periodic lattice modulation. Excellent qualitative agreement between calculated and experimental contrasts lends weight to the claim that these contrasts, observed over part of the composition range of liquid phase epitaxy grown In(x)Ga(1-x)As (y)P(1-y) alloys, are associated with spinodal decomposition.