Fabrication and Characterization of Porous Silicon Nanowires by MACE Technique

Silicon nanowire-based devices have properties that can outperform their traditional counterparts in many ways because of the Silicon nanowires have a high surface to volume silicon ratio and unique quasi-one-dimensional (1D) electronic structure. To fabricate silicon nanowires (SiNWs) are a variety of different approaches have been and these are classified into top-down and bottom-up methods. There are many different techniques to fabricate silicon nanowires, but most of these methods are expensive and time-consuming. In this thesis, we report the synthesis of porous silicon nanowires through the metalassisted chemical etching in a solution of hydrofluoric acid and hydrogen peroxide. Metalassisted chemical etching (MACE) method produces the porous silicon nanowires using an aqueous solution of hydrofluoric acid (HF) and hydrogen peroxide (H2O2). The porous silicon nanowires morphology and dimension were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray diffraction showed the crystal structure orientation of the porous silicon nanowires. From an application point of view, the porous silicon nanowires are both optically and electronically active. They find potential applications in diverse areas such as photocatalysis, lithium ion batteries, gas sensors and drug delivery and medical diagnostics. Porous silicon nanowires is a tremendous antireflective layer and have a great potential to be utilized in radial or coaxial p-n junction solar cells that could provide orthogonal photon absorption, antireflection, and enhanced carrier collection