Abstract: An electroless etching process. The process produces nanostructured semiconductors in which an oxidant (Ox1) is deposited as a metal on a semiconductor surface and used as a catalytic agent to facilitate reaction between a semiconductor and a second oxidant (Ox2). Ox2 is used to initiate etching by injecting holes into the semiconductor valence band as facilitated by the catalytic action of the deposited metal. The extent of reaction is controlled by the amount of Ox2 added; the reaction rate is controlled by the injection rate of Ox2. The process produces high specific surface area and/or hierarchically structured porous Si with higher and controllable yield. In addition, the ability is demonstrated to vary the pore size distribution of mesoporous silicon including producing hierarchically structured mesoporous silicon with more than one peak in the pore size distribution. In principle, the process applies to any semiconductor onto which metal can be deposited galvanically.

Abstract: A regenerative electroless etching process produces nanostructured semiconductors in which an oxidant (Ox1) is used as a catalytic agent to facilitate reaction between a semiconductor and a second oxidant (Ox2) that would be unreactive (or slowly reactive compared to Ox1) in the primary reaction. Ox2 is used to regenerate Ox1, which can initiate etching by injecting holes into the semiconductor valence band. The extent of reaction is controlled by the amount of Ox2 added; the reaction rate, by the injection rate of Ox2. This general strategy is demonstrated specifically to produce highly luminescent nanocrystalline porous, amorphous pillared, and hierarchical porous silicon from the reaction of V2O5 in HF(aq) as Ox1 and H2O2(aq) as Ox2 with a silicon-comprising substrate. The process can be performed on silicon-comprising substrates of arbitrary size and shape including powders, reclaimed shards, wafers, pillared silicon, porous silicon, and silicon nanowires.

Abstract: A regenerative electroless etching process produces nanostructured semiconductors in which an oxidant (Ox1) is used as a catalytic agent to facilitate reaction between a semiconductor and a second oxidant (Ox2) that would be unreactive (or slowly reactive compared to Ox1) in the primary reaction. Ox2 is used to regenerate Ox1, which can initiate etching by injecting holes into the semiconductor valence band. The extent of reaction is controlled by the amount of Ox2 added; the reaction rate, by the injection rate of Ox2. This general strategy is demonstrated specifically to produce highly luminescent nanocrystalline porous, amorphous pillared, and hierarchical porous silicon from the reaction of V2O5 in HF(aq) as Ox1 and H2O2(aq) as Ox2 with a silicon-comprising substrate. The process can be performed on silicon-comprising substrates of arbitrary size and shape including powders, reclaimed shards, wafers, pillared silicon, porous silicon, and silicon nanowires.