The formation of (111) twin lamellae in thin films was studied by using transmission electron microscopy. Voids in the thin films were related to the (111) twin lamellae. The voids were formed due to the incomplete coalescence of islands, and it was found that (111) twin lamellae appeared in order to accommodate the small misfit between growing islands during contact. In the case of planar defects, the formation of (111) twin lamellae was attributed to the maintenance of a TiO6 octahedron and its relationship to an hexagonal BaTiO3 structure. The very narrow width of the twin lamellae was attributed to the contact of 2 growing islands, and to the very small grain size of the thin films.

J.W.Jang, W.J.Cho, J.H.Lee, S.S.Choi, T.S.Hahn: Japanese Journal of Applied Physics - 1, 1997, 36[11], 6942-5