Formation of uni-directional ultrathin metallic YSi2 nanowires on Si(110)

Ultrathin YSi2 nanowires were grown epitaxially on the Si(110) surface. High-aspect-ratio nanowire growth is induced by the strongly anisotropic lattice-match between the silicide crystal lattice and the Si(110) surface, similar to the established formation of rare-earth silicide nanowires on Si(100). In contrast to the Si(100) case, however, YSi2 nanowires on Si(110) grow in a single orientation along the [11¯0] direction and exhibit a clear preference of nucleating at step edges when these edges are aligned along the [11¯0] growth direction. This suggests a promising avenue for the fabrication of regular nanowire arrays with controlled wire separation, by varying the miscut angle of the Si wafer. The nanowires are metallic and are embedded in a reconstructed Si(110)-(23×3)R54.7°-Y semiconducting surface layer.