Abstract: A process for etching a silicon-containing substrate to form structures is provided. In the process, a metal is deposited and patterned onto a silicon-containing substrate (commonly one with a resistivity above 1-10 ohm-cm) in such a way that the metal is present and touches silicon where etching is desired and is blocked from touching silicon or not present elsewhere. The metallized substrate is submerged into an etchant aqueous solution comprising about 4 to about 49 weight percent HF and an oxidizing agent such as about 0.5 to about 30 weight percent H2O2, thus producing a metallized substrate with one or more trenches. A second silicon etch is optionally employed to remove nanowires inside the one or more trenches.

Abstract: A process is provided for etching a silicon-containing substrate to form nanowire arrays. In this process, one deposits nanoparticles and a metal film onto the substrate in such a way that the metal is present and touches silicon where etching is desired and is blocked from touching silicon or not present elsewhere. One submerges the metallized substrate into an etchant aqueous solution comprising HF and an oxidizing agent. In this way arrays of nanowires with controlled diameter and length are produced.

Abstract: A nanostructured optoelectronic device is provided which comprises a nanostructured material and a host material intermingled with the nanostructured material. The host material may have a higher index of refraction than the nanostructured material. The host material's index of refraction may be chosen to maximize the effective active area of the device. In an alternative embodiment, the host material comprises scattering centers or absorption/luminescence centers which absorb light and reemit the light at a different energy or both.