Preparation of Iron and Gold Silicide Nanodomains on Silicon (111) by the Reaction of Gold, Iron-Gold-Core Shell, and Alloy Nanoparticles with Triethylsilane

This study describes a strategy to use composite colloidal nanoparticles and triethylsilane as precursors to synthesize nanometer size structures on single-crystal silicon substrate. The concept is demonstrated by depositing gold, iron-gold alloy, and iron-gold core-shell nanoparticles on silicon (111). Upon heating, the nanoparticles form new crystalline phases on the Si (111) surface. Atomic force microscope (AFM) data show the collapse of the iron gold core-shell and alloy nanoparticles at temperatures 100-200 degrees C higher than gold nanoparticles, indicating the efficient tethering of iron containing nanoparticles on silicon (111). Both structural analysis and X-ray spectroscopy show that the iron-gold alloy and iron-gold core-shell nanoparticles successfully form the semiconducting beta-FeSi2 phase at relatively low temperature. The stabilities of the silicide are assessed at elevated temperatures. Silicon successfully nucleates on the created nanostructures, which suggests strong catalytic activity towards producing further nanostructures on the surface.