Si NWs conversion to Si-SiC core-shell NWs by MBE

Abstract

Si nanowires (NWs) have been converted to silicon-silicon carbide (Si-SiC) core-shell NWs at different conditions of substrate temperature in an ultra-high vacuum using a molecular beam epitaxy (MBE) set-up. In-situ auger electron spectroscopy (AES) and reflection high-energy electron diffraction (RHEED) allowed a control of the growth process. To evaluate structure and chemical modifications of their shape, scanning electron microscopy (SEM) and conventional transmission electron microscopy (TEM) is used. Evidence of Si-carburization is shown by electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED) related investigation. Facet dependence of the carbon diffusion is shown with a maximum carburization depth of 20nm on the (331) and (131) facet of the NWs. Si-SiC core-shell NWs free of planar defects have been obtained for conversion temperatures lower than 800ºC.