Silicon nanowires (SiNWs) with desirable axial crystallographic orientations can be readily prepared by a novel chemical‐etching technique (see SEM image). The as‐synthesized SiNW arrays significantly suppress reflection over the visible‐light spectral range and are therefore promising candidates for antireflection coatings of photovoltaic cells despite exhibiting a lower efficiency than non‐nanowire‐based devices at this stage of development.

A novel strategy for preparing large‐area, oriented silicon nanowire (SiNW) arrays on silicon substrates at near room temperature by localized chemical etching is presented. The strategy is based on metal‐induced (either by Ag or Au) excessive local oxidation and dissolution of a silicon substrate in an aqueous fluoride solution. The density and size of the as‐prepared SiNWs depend on the distribution of the patterned metal particles on the silicon surface. High‐density metal particles facilitate the formation of silicon nanowires. Well‐separated, straight nanoholes are dug along the Si block when metal particles are well dispersed with a large space between them. The etching technique is weakly dependent on the orientation and doping type of the silicon wafer. Therefore, SiNWs with desired axial crystallographic orientations and doping characteristics are readily obtained. Detailed scanning electron microscopy observations reveal the formation process of the silicon nanowires, and a reasonable mechanism is proposed on the basis of the electrochemistry of silicon and the experimental results.

Neatly scratching the surface: A facile etching technique assisted by a silver‐nanoparticle network to produce large‐area 1D silicon nanostructure arrays with desired orientation and doping characteristics is demonstrated (see picture). A mechanism for the highly selective etching is proposed on the basis of experimental evidence.

A straightforward metal-particle-induced, highly localized site-specific corrosion-like mechanism was proposed for the formation of aligned silicon-nanowire arrays on silicon in aqueous HF/AgNO3 solution on the basis of convincing experimental results. The etching process features weak dependence on the doping of the silicon wafers and, thus, provides an efficient method to prepare silicon nanowires with desirable doping characteristics. The novel electrochemical properties between silicon and active noble metals should be useful for preparing novel silicon nanostructures and also new optoelectronic devices.

A method involving dry deposition plus wet chemical etching was devised to fabricate silicon nanowire (SiNW) arrays and to study silver catalysis during fabrication. Through investigation of the track of catalyst particles, it was shown that Ag really catalyses the etching of silicon underneath Ag, which clarifies doubts about the formation of SiNW arrays during wet chemical etching. The intrinsic properties of Ag and the network structure of Ag clusters during etching facilitate the etching process. The etching product, i.e. vertical SiNW arrays containing an Ag nanocluster mesh, could be considered as a prototype secondary composite nanostructured catalyst with promise for future applications.