Growth of nanostructured silicon by microwave/nano-susceptors technique with low substrate temperature

We present a new technique which allows the growth of silicon nanostructures at low temperature, in different forms. The growth takes place with the presence of a gaseous silicon precursor and a metal catalyst, once the eutectic temperature is overcome. The technique we present is based on heating limited to the metal nanoparticles, by irradiation of Microwaves. The so called nano-susceptors absorbs energy that produces large local increase of temperature. Only the metal nanoparticles reach high temperatures. The substrate, due to the lower conductivity, does not heat up and remains at 200 °C. Different conformations of silicon nanostructures can be obtained with different crystallographic structures, depending on the energy delivered to the surface. As a particular case, at the lowest energies, we evidence the presence of BC8[sbnd]Si. This configuration of the crystal, otherwise very difficult to obtain, represent a nanowires characteristic which can be particularly useful for the development of integrated sensors due to the very high conductivity. Finally, the chemical analysis of the samples surface with nanostructured silicon evidenced a high reactivity, with different degree depending on the silicon structures shape.