Synthesis of Fe nanoparticles by redox reaction using an electron beam deposition technique

Abstract

A new technique for synthesizing Fe nanoparticles based on an electron beam deposition technique from a Fe 2O 3 source has been developed. We deposited Fe 2O 3 films directly on Si(001) substrates, Al and Cu buffer layer, and observed the formation of Fe nanoparticles at the Si(001) and Al interfaces respectively. The Al at the interface is oxidized to Al 2O 3 and Si is oxidized to SiO 2. For films deposited on Cu buffer layer, however, no Fe nanoparticles were formed. We explain our results in terms of the enthalpy of formation of the oxides. The enthalpy of formation of SiO 2 and Al 2O 3 is much lower than that of Fe 2O 3, thus promoting the formation of Fe nanoparticles. The enthalpy of formation of CuO is however, greater than that of Fe 2O 3 thus forbidding the formation of Fe nanoparticles. This is in agreement with both X-ray Photoelectron Spectroscopy (XPS) depth profile analysis and Transmission Electron Microscopy (TEM).