Thermodynamic driving forces governing assembly of disilicide nanowires

Driving forces are investigated for assembling low dimensional, metallic, erbium and dysprosium disilicide nanowires on Si(001), using both scanning probe microscopy and density functional theory. Side-by-side comparison between emulated and measured scanning tunneling microscopy images allows establishment of reliable atomic models for complex adatom surface reconstructions of Er/Si(001) and Dy/Si(001) that are precursors to high aspect ratio disilicide nanowires. Peculiar surface reconstructions and relaxation of Si bonds are identified as the key factors for nucleation of these disilicide nanowires in parallel arrays on vicinal Si(001). Stable nanowire widths and heights are calculated with predicted atomic models that are consistent with experimental observations. A clear understanding of the nanowire-substrate interface is determined by correlating adatom reconstruction patterns with nanowire formation that is imperative to the development of unique procedures for massive fabrication of monodisperse nanosystems.