Copper silicide/silicon nanowire heterostructures: in situ TEM observation of growth behaviors and electron transport propertiesElectronic supplementary information (ESI) available: Four ESI to demonstrate the fabrication procedures of in situ TEM samples, the temperature effect on copper silicide growth, different zone axis of -Cu3Si structure and derivation of activation energy. Three in situ TEM videos as ESI online material to present dynamic observation of the formation of -Cu3Si/Si/-Cu3Si

Copper silicide has been studied in the applications of electronic devices and catalysts. In this study, Cu 3 Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM). The dynamic diffusion of the copper atoms in the growth process and the formation mechanism are characterized. We found that two dimensional stacking faults (SF) may retard the growth of Cu 3 Si. Due to the evidence of the block of edge-nucleation (heterogeneous) by the surface oxide, center-nucleation (homogeneous) is suggested to dominate the silicidation. Furthermore, the electrical transport properties of various silicon channel length with Cu 3 Si/Si heterostructure interfaces and metallic Cu 3 Si NWs have been investigated. The observations not only provided an alternative pathway to explore the formation mechanisms and interface properties of Cu 3 Si/Si, but also suggested the potential application of Cu 3 Si at nanoscale for future processing in nanotechnology. Cu 3 Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM).