The Van der Waals epitaxial growth of GaSe on Si(111)
Date
1997
Authors
Nicolet, Marc-A., author
Song, J. G., author
Vantomme, André, author
Mahan, John E., author
Eddrief, M., author
Le Thanh, Vinh, author
American Institute of Physics, publisher
Journal Title
Journal ISSN
Volume Title
Abstract
GaSe, a layered semiconductor, may be grown on the Si(111) surface by molecular beam epitaxy. The crystalline quality is relatively good, in the sense that the MeV4He ion minimum channeling yield (~30%) is as low as that of state-of-the-art bulk material, and the interface is atomically abrupt. The initial film deposits are epitaxial islands, and subsequent growth is in the Frank-van der Merwe mode. With the islands already relaxed at the nucleation stage and coalescing to essentially uniform coverage with the first monolayer of deposition, GaSe on Si(111) provides an example of van der Waals epitaxy. However, it is difficult to understand how epitaxy (crystallographic alignment with the substrate) can occur in such a case, where the film is incommensurate starting from the initial nuclei. A mechanism for alignment of the islands is proposed: they are aligned with the silicon substrate through the influence of dangling bonds at their perimeter, being "quasi-commensurate" by virtue of their small lateral size. Although discommensurate regions are created as the islands grow laterally, there is simply no change in their orientation.