Porous Silicon - A Nanostructured Delivery System

Nanostructured porous silicon is increasingly being used in a range of applications, including; optoelectronic devices, bio-sensors and drug delivery therapies. Porous silicon may be prepared by anodization or stain etching, with the surface porosity and chemical composition determined by the process used; this correlation has been characterized using a range of physicochemical methods. Nitrogen gas adsorption determined the porous silicon specific surface area, while X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) have characterized the surface chemical features. Significant differences in the porous and surface chemical properties of stained etched and anodized pSi have been identified. Specific surface areas of 254.06 0.34 and 300.24 0.39 m²/g were determined for anodized and stain etched powders respectively via nitrogen gas adsorption. Fourier transform infrared spectroscopy identified Si-H_x (x=1 - 3) species on the surface as well as evidence of oxidation and hydrocarbon contamination.