Spectroscopic studies of silicon nanostructures fabricated using metal induced etching

Abstract

The present thesis focuses on study of low dimensional semiconductor systems by investigating surface morphology, optical and electronic properties. For this purpose, well aligned silicon nanowires (SiNWs) have been fabricated using metal-induced etching technique and used for spectroscopic studies. Silver (Ag) and gold (Au) nanoparticles have been used in the present study for the fabrication of SiNWs and their role in nanowire microstructures have been understood. Scanning electron microscopy (SEM) and room temperature photoluminescence (PL) measurements were performed to study surface morphology of SiNWs and to confirm the presence of quantum confinement effect. Variation of the band gap in SiNWs has been studied using Diffuse Reflectance Spectroscopy. In order to understand different phenomena taking place at nanoscale, Raman measurements were carried out and the effect of confinement, doping level and electron-phonon interactions (Fano) on Raman line shapes have been discussed in detail. Moreover, a theoretical framework has been proposed to study the interplay between phonon confinement and electron-phonon interactions (Fano effect) at the nanoscale.