Formation of manganese silicide nanowires on Si(111) surfaces by the reactive epitaxymethod

Abstract

Manganese silicide nanowires (NWs) with a largelength/width ratio have been predominantly formed on Si(111)-7 × 7 surfaces with the reactive epitaxy method by a delicate control of growth parameters. Thesupply of free Si atoms per unit time plays a crucial role in the formation of the NWs. High growthtemperature and low Mn deposition rate are favorable for the growth of long NWs with a largelength/width ratio and the formation of islands with other shapes can be greatly restrained under theseconditions. The formation of NWs is driven by the minimization of the strain energy caused bythe lattice mismatch between the silicide and substrate. Scanning tunneling spectroscopymeasurements show that the NWs exhibit a semiconducting character with a band gap of∼0.8 eV, which is consistentwith that of bulk MnSi1.7.