A study on formation and physico-chemical properties of Pt silicide nanowires on Si(100) surface

Abstract

$\bold{Structures and Electronic Properties of Self-assembled Pt Silicide Nanowires on Si(100)$ We investigated the formation of Pt silicide nanowires on a Si(100) surface using scanning tunneling microscopy and high-resolution photoemission spectroscopy. Pt silicide nanowires with a tetragonal Pt2Si structure are formed along the step edges of Si(100). Pt-induced c(4 $\times$ 2) reconstructions also appear adjacent to the tetragonal $Pt_2Si$ nanowires. Formation of the $Pt_2Si$ nanowires is attributed to the anisotropic lattice mismatches between the tetragonal $Pt_2Si$ structure and Si(100). Scanning tunneling spectroscopy data show that the nanowires are metallic. The stoichiometry of Pt silicide is confirmed by high-resolution photoemission spectroscopy. $\bold{Unidirectional Pt Silicide Nanowires Grown on Vicinal Si(100)}$ The formation and electronic properties of unidirectional $Pt_2Si$ nanowires grown on a Si(100)-2° off surface were investigated. We found that $Pt_2Si$ nanowires were formed along the step edge of Si(100)-2° off surface with c(4$\times$6) reconstructions occurred on the terrace of Si(100) using scanning tunneling microscopy and low energy electron diffraction. Stoichiometry of grown nanowires was found to be $Pt_2Si$ by high resolution core-level spectroscopy. Electronic band structures parallel and perpendicular to the nanowire direction are found anisotropic. The surface state induced by $Pt_2Si$ nanowires was also observed in the angle-resolved photoemission spectra taken along the nanowires. A clear free-electron like band dispersion was not observed in the valence level spectra, however, the existence of the density of states at the Fermi energy level indicates that $Pt_2Si$ nanowires are metallic. $\bold{Resistivity Measurement of Pt Silicide Nanowires Using Double-Scanning-Probe Tunneling Microscopy}$ The resistivities of Pt silicide nanowires with the widths less than 10 nm were measured. Pt silicide nanowires consist ...