Synthesis and reactivity of Fe nanoparticles embedded in a semi-insulating matrix

Abstract

The technique of plasma enhanced chemical vapor deposition has been used to synthesize Fe nanoparticles in an amorphous boron carbide matrix. The nanoparticles range in size from approximately 0.7 to 4.5 nm. It has been demonstrated that the size of the nanoparticles is proportional to the density of the Fe precursor (ferrocene) in the vapor. The matrix films have been found to be extremely hygroscopic. Upon absorption of moisture the films buckle and delaminate from the Si substrate. The buckling is a consequence of induced strain arising from the transformation of the Fe nanoparticles into α-Fe2O3. The formation of α-Fe2O3 has been verified by electron diffraction and near edge x-ray absorption fine structure measurements. Examination of the magnetic properties of the α-Fe2O3 using the technique of magnetic circular dichroism indicate that the nanoparticles are not ferromagnetic. © 2000 American Institute of Physics.