Rare-earth disilicide nanowires on flat and vicinal Si(100) surfaces: growth and characterization

Abstract

Bidirectional Hexagonal Gd Disilicide Nanowires on flat Si(100)-2×1 The growth of hexagonal Gd disilicide nanowires on Si(100) is studied by scanning tunneling microscopy. Gd disilicide nanowires are grown on Si(100) by submonolayer Gd deposition on the substrate at 600℃. The formation of nanowires is shown to be due to anisotropic lattice mismatches between hexagonal Gd disilicide and Si. The nanowires have widths of several nanometers and lengths up to micrometer length scales. The top of the nanowires has a c(2×2) structure, indicating that the crystalline structure is Si-deficient Gd disilicide. The nanowires were shown to have metallic properties using scanning tunneling spectroscopy. Unidirectional Hexagonal Gd Disilicide Nanowires on Vicinal Si(100)-2×1 The growth of unidirectional hexagonal Gd disilicide nanowires on vicinal Si(100) with a miscut of 2° toward [1 1 0] azimuth is studied by scanning tunneling microscopy. Compared with the flat Si(100) surface, hexagonal Gd disilicide nanowires are grown with unidirectional direction along [0 $\bar{1}$ 1] which is perpendicular to the single-domain dimer row direction of 2° off vicinal Si(100) at 600℃. STM results showed that the atomic structure of these nanowires is Si-deficient hexagonal $GdSi_2-x$ with a c(2×2) structure. The single nanowires had lateral widths of 2.1 nm and lengths are almost unlimited due to no obstacles such as perpendicularly grown nanowires and bunched steps; the high aspect ratios of the nanowires are derived from anisotropic lattice mismatches between the hexagonal $GdSi_2-x$ and the substrate Si. Scanning tunneling spectroscopy confirmed the metallic properties of the nanowires. Atomic wires on Flat and Vicinal Si(100)-2×1 The atomic wires grown by the Gd induced substrate reconstruction of flat and vicinal Si(100) with a miscut angle of 2° off toward [1 1 0] is studied using scanning tunneling microscopy and scanning tunneling spectroscopy. The atomic row are formed on the bot...