Abstract: A composition comprises a semiconductor substrate having a crystallographic plane oriented parallel to a surface of the substrate and at least one planar semiconductor nanowire epitaxially disposed on the substrate, where the nanowire is aligned along a crystallographic direction of the substrate parallel to the crystallographic plane. To fabricate a planar semiconductor nanowire, at least one nanoparticle is provided on a semiconductor substrate having a crystallographic plane oriented parallel to a surface of the substrate. The semiconductor substrate is heated within a first temperature window in a processing unit. Semi-conductor precursors are added to the processing unit, and a planar semiconductor nanowire is grown from the nanoparticle on the substrate within a second temperature window. The planar semiconductor nanowire grows in a crystallographic direction of the substrate parallel to the crystallographic plane.

Abstract: A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a silicon surface. The surface is then etched in a solution including HF and an oxidant for a brief period, as little as a couple seconds to one hour. A preferred oxidant is H2O2. Morphology and light emitting properties of porous silicon can be selectively controlled as a function of the type of metal deposited, Si doping type, silicon doping level, and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

Abstract: A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a Group III-V material surface. The surface is then etched in a solution including HF and an oxidant for a preferably brief period, as little as a couple seconds to one hour. A preferred oxidant is H2O2. Morphology and light emitting properties of porous Group III-V material can be selectively controlled as a function of the type of metal deposited, doping type, doping level, metal thickness, whether emission is collected on or off the metal coated areas and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

Abstract: A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a Group III-V material surface. The surface is then etched in a solution including HF and an oxidant for a preferably brief period, as little as a couple seconds to one hour. A preferred oxidant is H2O2. Morphology and light emitting properties of porous Group III-V material can be selectively controlled as a function of the type of metal deposited, doping type, doping level, metal thickness, whether emission is collected on or off the metal coated areas and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.