Silicon nanowire (SiNW) ensembles with vertical and zig-zag architectures have been realized using wet chemical etching of bulk silicon wafers (p-Si(111) and p-Si(100)) with an etching hard mask of silver nanoparticles that are deposited by wet electroless deposition on polystyrene pattered silicon surfaces.

 

Strong visible (red-orange) room temperature photoluminescence has been observed in wet chemically etched heavily (1020 cm-3) and lowly (1015 cm-3) doped SiNWs. Our observations strongly suggest that visible light emission at room temperature of SiNWs is a result of the rough sidewall structure that can be such that nanoscale features form that make quantum confinement most probable. Significant light absorption (over 90% in a range between 300-2000 nm) was observed in the SiNWs covered by the TCO (Al doped ZnO) thin layers performed via Atomic Layer Deposition. The strong absorption, less reflection of visible and infra-red light and room temperature photoluminenscence of the SiNW ensembles strongly suggest that such a material has a real potential to be applied in the fields of opto-electronics, photonics, sensoric and photovoltaics. The morphology, crystallographic and surface structure, and optical properties of SiNWs will be presented and discussed in details.