Porous Silicon/Iron Oxide Nanocomposites with Deposition Dependent Magnetic Properties

The combination of porous silicon (PS) with iron oxide nanoparticles results in a nanocomposite system offering a magnetic behavior which is influenced by the properties of the nanosized particles but also by the morphology of the matrix. Mesoporous silicon, fabricated by anodization of a highly n-doped silicon wafer offers oriented pores with average diameters of 50 nm and 90 nm, respectively. Fe3O4 nanoparticles of different size (3.8, 5 and 8 nm) have been used to deposit into the pores of these matrices. The resulting composite exhibits a desired transition temperature between superparamagnetic (SPM) behaviour and blocked state which can be modified by the size of the deposited particles, the distance between the particles and by the variation of the used porous silicon morphology, respectively. Beside scanning electron microscopy (SEM) a sophisticated method for TEM-investigations has been employed to figure out the various characteristics of the system.