Self-formation of Fe/Fe-O nanoparticles in porous SiO₂films

Abstract

Self-formation of Fe/Fe-O particles in porous SiO2 films has been studied by investigating the structure and physical properties of hybrid samples SiO2:Fe/SiO2/Si. The sol-gel spin-on technique was used for the formation of Fe-doped silica films on silica-coated Si wafers. The sol was prepared from precursors composed of ethanol and/or aqueous solutions of tetraethoxysilane (TEOS) and FeCl3. As-grown hybrid samples were annealed in Ar atmosphere. Structural studies by means of atomic force microscopy (AFM) have shown a different morphology of samples produced from precursors with various Fe-amount. Spectroscopic ellipsometry measurements were carried out for characterization of the contribution of Fe/Fe-O clusters to the optical response of hybrid samples. Magnetic properties of Fe-doped silica films were studied by measuring the magnetic field and temperature dependences of magnetization. Experimental data were interpreted taking into account particular features of Fe and Fe-O nanoparticles in silica matrix.