The origin of typical extended defects in semiconductor heterostructures with heterovalent interfaces was revealed. That is, pairs of stacking faults in pseudomorphic ZnSe epitaxial layers grown on a GaAs(001) substrate. Structural images of the defects were obtained by means of high-resolution transmission electron microscopy. Analysis of the images, combined with first-principles energy calculations, clarified the atomistic structure of the extended defects. An intrinsic stacking fault on (111) intersects the other one on (11¯1) on the interface between the epitaxial layer and the substrate, forming an intersecting line along [1¯10]. Around the intersecting line, it was found that Ga, As and Se atoms formed the specific reconstructed structure with relatively low formation energy, which corresponds well to a reconstructed surface structure on GaAs(001) with excess As and additional Se atoms. The stability of extended defects was therefore

attributed to the reconstructed surface structure on the substrate, formed before epitaxial growth.

Origin of a Pair of Stacking Faults in Pseudomorphic ZnSe Epitaxial Layers on GaAs. Y.Ohno, N.Adachi, S.Takeda: Applied Physics Letters, 2003, 83[1], 54-6