Thin films of the lamellar semiconductor were grown onto various Si surfaces: Se-Si(111), Si(111)-(7 x 7), Ga(3 x 3)-Si(111) and H-Si(111). The films were then investigated by using transmission electron microscopy. Cross-sectional observations revealed a well-defined epitaxy: GaSe(001)||Si(111) and GaSe[100]||Si[110]. The GaSe -phase was frequently observed in the films, but stacking faults occurred on GaSe planes. Planar view images exhibited 3 moiré patterns at 120 which involved Si 220 and GaSe 110 type spots. The moiré fringe spacing of about 8.5nm indicated a GaSe lattice which was relaxed with respect to the Si lattice. A residual lattice extension of about 0.4% remained in the GaSe film, as compared with the bulk material, and was suggested to be due to stacking faults. Electron diffraction studies of the planar view revealed the existence of GaSe 100 type spots which were forbidden for the -phase. These spots were related to the presence of stacking faults.

A.Koëbel, Y.Zheng, J.F.Pétroff, M.Eddrief, L.T.Vinh, C.Sébenne: Journal of Crystal Growth, 1995, 154[3-4], 269-74