Micro-Raman and field emission studies of silicon nanowires prepared by metal assisted chemical etching

TL;DR

This study investigates silicon nanowires created by metal assisted chemical etching, analyzing their structural properties via Raman scattering and their electron emission capabilities, revealing size-dependent enhancements suitable for field emission devices.

Contribution

It demonstrates that MACE produces well-aligned SiNWs with size-dependent optical and electron emission properties, advancing their application potential.

Findings

Raman shift indicates quantum confinement effects in SiNWs.

Field emission improves as SiNW diameter decreases.

MACE effectively produces aligned SiNWs for device applications.

Abstract

Micro-Raman scattering and electron field emission characteristics of silicon nanowires (SiNWs) synthesized by metal assisted chemical etching (MACE) are investigated. Scanning electron microscopy images reveal the growth of well aligned vertical SiNWs. Raman shift and size relation from bond-polarizability model has been used to calculate exact confinement sizes in SiNWs. The Si optical phonon peak for SiNWs showed a downshift and an asymmetric broadening with decreasing diameter of the SiNWs due to quantum confinement of optical phonons. The field emission characteristics of these SiNWs are studied based by carrying out current-voltage measurements followed by a theoretical analysis using Fowler-Nordheim equation. The electron field emission increased with decreasing diameter of SiNWs. Field emission from these SiNWs exhibits significant enhancement in turn-on field and total emission current with decreasing nanowire size. The reported results in the current study indicate that MACE is a simple technique to prepare well-aligned SiNWs with potentials for applications in field emission devices.