Self‐catalytic etching of silicon: from nanowires to regular mesopores

Metal assisted etching is a new promising technique for Silicon nanowires fabrication, but also for generating a new class of porous semiconductors with precise and controlled morphology, unavailable by electrochemical etching. The process and the morphology seem to be independent on substrate doping, but only on the crystallographic directions and metal patterning at the top surface. A preliminary investigation on some possible patterning techniques is reported, using porous silicon layers as pre‐patterning tool, porous alumina and polystyrene nanospheres. The influence of the masking procedure on the final array of nanostructures is discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)