Synthesis and Characterization of Silicon Nanostructures by using Porous Silicon as a Seed Material

Nanostructured porous silicon is considered to be a potential candidate in the fields of information and communication technologies owing to its light emission in the visible region. The porous silicon (pSi) can be achieved by electrochemical etching (or anodization) of Si in HF based electrolytic solution. Tunable structural and optical properties of pSi have been achieved by playing with etching parameters during anodization. The inherent size dependant tunable property of pSi makes them a seed material for the generation of isolated low dimensional Si nanostructures by subsequent physical techniques like laser ablation, oxide assisted growth and ultrasonication of free-standing pSi. It is found that, these structures appear to be identical but their optical responses differ drastically. Further, the fabrication of porous silicon based distributed Bragg reflectors with a tunable wave reflection are useful for optical communications. Moreover, the alternative irradiation treatments (i.e. gamma and high energy heavy ion) have also been used to observe the effective modifications in the structural and optical properties. The size and shape modifications and the tunable properties of these nanostructures are sufficient to integrate the compatibility of electronic and optoelectronic functions in a single silicon chip. 

Keywords: Porous silicon, Nanostructures, Optical properties, Structural properties, Irradiation modifications.