Growth behaviour of Ge nano-islands on the nanosized Si{111} facets bordering on two {100} planes

Si(100) substrates were used to fabricate various nanosized {111} facets between the (100) planes using photolithography and anisotropic wet chemical etching. Following simultaneous Ge chemical vapour deposition on the neighbouring (100) and {111} facets, the Ge nano-island formation and distribution was observed on both the (100) terraces and the {111} side walls using a dynamical atomic force microscope. The nano-island formation on the nanosized {111} strip facets was found to be strongly suppressed upon reducing the strip width due primarily to the interaction of adatoms on the neighbouring facets. Specifically, the difference in the effective chemical potential of Ge adatoms on the two neighbouring facets leads to the depletion of nano-islands on the {111} strip with width <500 nm under the growth condition used in this study.