A transmission electron microscopic study was made of epitaxial C films which had been grown onto a (001) GeS surface. The relationship between the orientation of the substrate and that of the films was studied, as were structural defects (such as grain boundaries), in the films, which were unknown in the bulk C60 or C70 crystals. Small misalignments of the over-layers with respect to the orientation of the substrate (so-called epitaxial rotations) existed mainly in C70 films, but were sometimes observed in C70 over-layers. A simple symmetry model, which had previously been used to predict the rotation of hexagonal over-layers on hexagonal substrates, was checked numerically and was applied to the present system.

D.Bernaerts, G.Van Tendeloo, S.Amelinckx, K.Hevesi, G.Gensterblum, L.M.Yu, J.J.Pireaux, F.Grey, J.Bohr: Journal of Applied Physics, 1996, 80[6], 3310-8