Sequential growth of self-organized epitaxial FeSi2 and CoSi2 nanostructures on Si(1 1 1)-7 × 7 surfaces

Abstract

Epitaxial γ-FeSi2 and CoSi2 nanostructures, grown on a vicinal Si(111)-7 × 7 surface by sequentially depositing 1-monolayer (ML) of Fe and 1ML of Co on a hot Si substrate under ultrahigh vacuum condition, have been investigated by in-situ scanning tunneling microscopy, ex-situ field emission scanning electron microscopy and x-ray photoemission spectroscopy (XPS). While γ-FeSi2 nanostructures have grown as nanowires along the three equivalent 〈110〉 directions on the Si(111) surface, CoSi2 nanoislands have grown as equilateral triangular and trapezoidal islands. Such self-organized nanostructures may find applications in nanoscale devices including S-F hybrids for quantum technology, as CoSi2 is a superconductor (S) and γ-FeSi2 is a ferromagnet (F).