Epitaxial growth of erbium silicide nanowires on silicon(001)

Submonolayer amounts of Er deposited onto Si(001) react with the substrate to form epitaxial nanowires of crystalline ErSi2. The ErSi2 nanowires are <1 nm high, a few nanometers wide, close to a micron long, and crystallographically aligned to Si〈110〉 directions. The growth of uniaxial structures occurs because the different crystal structures of ErSi2 and Si have a good lattice match along one Si〈110〉 crystallographic axis (−1.3%) but a significant mismatch along the perpendicular Si〈110〉 axis (+6.5%). An energetic model explains the formation of the ErSi2 nanowires.