Contactless characterization of porous silicon structures by four-wave mixing and microwave techniques

We apply optical contactless techniques, namely the four-wave-mixing and mi crowave harmonics generation for the characterization of nanocrystalline fr ee-standing films and platelets of microcrystalline porous silicon. We obse rve (i) full carrier localization and significant lifetime shortening in fr ee-standing films, which is thought to be a manifestation of their low-dime nsional confinement, (ii) increased carrier lifetime in microcrystalline po rous silicon, presumably originating from passivated surface states at the surface of pores.