Abstract
Arrays of aligned silicon nanoribbons were prepared on silicon substrates in the solution containing aqueous HF and AgNO3 by metal-nanoparticel-assisted etching technique. The in situ investigations of a solid-state reaction where the silicon nanoribbons transformed into nickel silicide nanoribbons are achieved in the silicon nanoribbons/Ni grid system. The results indicate that Ni atoms are still the dominant diffusing species in Ni/Si system at nanometer scale. The condition for the in situ experiments is under Ni-rich situation so that the final phases of the formed silicides are all Ni-rich phases. We also investigate the transformation of Si nanoribbons into nickel silicide nanoribbons at elevated temperature. The activation energy (1.06 eV) for the growth of nickel silicide nanoribbons was obtained from an Arrhenius plot. The approach is useful to clarify the silicidation mechanisms and phase transformation at the nanoscale. In addition, using the method of comparison of the experimental high-resolution TEM images with the simulated images, the thickness of nanoribbons could be determined.