Drying Techniques Applied to Porous Silicon
Wet-etched mesoporous silicon is normally dried in the air, but this limits the range of porosities and surface areas achievable, due to capillary force-induced collapse of the silicon skeleton. This updated review discusses the various alternative drying techniques with particular attention paid to supercritical/critical point drying, a powerful technique applicable to all physical forms of porous silicon. Optimized etching and supercritical drying conditions have recently led to the achievement of silicon powder surface areas up to 1125m2/g from anodized p− wafers and pore volumes up to 4.66 ml/g from anodized p + wafers. Supercritical drying has also been used to minimize “bundling” of porous silicon nanowires in closely spaced arrays.
KeywordsPorous silicon drying supercritical drying
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