Silver: a novel growth catalyst for Ge nanoislands on Si(113)

Abstract

The impact of silver pre-adsorption on germanium growth on Si(113) was investigated using in-situ low-energy electron microscopy (LEEM) as well as low-energy electron diffraction (LEED). The adsorption of silver leads to the formation of a regular pattern of nanofacets along the [10] direction. The periodicity of this pattern in [33] direction was determined to (44 ± 4) nm. From LEED series at different energies the facets were identified to be of (111) and (115) orientation. While the (111) facets show a (√3 × √3)-R30° reconstruction, the (115) facets exhibit a (2 × n) superstructure. The subsequent growth of Ge results in the formation of nanoislands that are aligned along the facets. These Ge islands have an anisotropic shape with typical sizes of about 100 nm in [33] direction and 400 nm in [10] direction. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)