Very thin GaSe films, about 100Å thick, were epitaxially grown by molecular beam epitaxy onto variously ordered Si(111) substrates: the clean 7 x 7 reconstructed surface with its dangling bonds, the H-passivated 1 x 1 surface and the Ga-passivated (√3 x √3)R30° reconstructed one. For each substrate, the GaSe layer and its interface with Si were studied by low energy electron diffraction, Auger electron spectroscopy and photo-emission yield spectroscopy. Upon sequential removal of the GaSe film by Joule heating in ultrahigh vacuum, it was shown that the band offsets were not sensitive to the initial surface structure of the substrate, the uniformity of the GaSe layer and of the Fermi level position was questionable on Si(111) √3Ga and the density of gap states in the GaSe layer increased upon aging in air.

Influence of Surface Reconstruction on MBE Growth of Layered GaSe on Si(111) Substrates. H.Reqqass, J.P.Lacharme, M.Eddrief, C.A.Sébenne, V.Le Thanh, Y.L.Zheng, J.F.Pétroff: Applied Surface Science, 1996, 104-105, 557-62