Fabricating well controlled nanostructures and obtaining precise structural, electrical, and optical information from them are essential for understanding the intrinsic properties of silicon (Si) nanostructures, which in turn is important for exploring the potential of quantum confinement induced light emission from crystalline Si. A combination of high resolution electron beam lithography, anisotropic reactive ion etching (RIE), and thermal oxidation has been successfully applied to obtain sub-5 nm Si columnar structures. A transmission electron microscopy (TEM) technique has also been used to characterize the precise structural dimensions of these columns. To obtain the electrical and optical information, a process based on polyimide planarization was developed to establish electrical contacts to these nanostructures. The same process is also applicable for fabricating device structures to study electrically pumped optical response. Preliminary transport studies have confirmed current conduction through the Si nano-pillars and yielded an estimate of the conductivity.