Contactless Characterization of porous Silicon Structures by Four-Wave Mixing and Microwave Techniques

摘要

We apply optical contactless techniquws, namely the four-wave-mixing and microwave harmonics generation for the characterization of nanocrystalline free-standing films and platelets of microcrystalline porous silicon. We observe(i) full carrier localization and significant lifetime shortening in free-standing films , which is thought to be a manifestation of their low-dimensional confinement, (ii) increased carrier lifetime in microcrystalline porous silicon, presumably originating from passivated surface states at the surface of pores.