The dislocation structures in thin films that had been grown epitaxially onto [001]-oriented MgO or SrTiO3 single crystals were studied by means of conventional and high-resolution transmission electron microscopy. The high-resolution cross-sectional images from films that had been grown onto MgO exhibited misfit dislocations with a Burgers vector of ½<010> and a line direction of <100>. The latter were identified by imaging the interface in 2 non-parallel zone axes. Plan-view studies of films that had been grown onto SrTiO3 revealed dislocations with a Burgers vector of <010> that lay along <100> directions in the plane of the film. The high-resolution microscopy of cross-sectional samples revealed dislocations that had an additional half-plane on the substrate side of the film. This was the opposite to that which was required in order to accommodate the lattice misfit at room temperature.

S.Stemmer, S.K.Streiffer, F.Ernst, M.Ruhle: Physica Status Solidi A, 1995, 147[1], 135-54