Light-matter interaction of single semiconducting AlGaN nanowire and noble metal Au nanoparticle in the sub-diffraction limit

TL;DR

This study investigates the near-field light-matter interactions of a single semiconducting AlGaN nanowire and an attached gold nanoparticle using NSOM, revealing defect-related electronic transitions and plasmonic effects at sub-diffraction scales.

Contribution

It provides new insights into the optical interactions at the nanoscale involving AlGaN nanowires and gold nanoparticles using NSOM imaging.

Findings

Defect-related electronic transitions influence NSOM images.

Surface plasmon resonance enhances local optical fields.

NSOM reveals sub-diffraction limited light-matter interactions.

Abstract

The near field scanning optical microscopy (NSOM) is not only a tool for imaging of sub-diffraction limited objects but also a prominent characteristic tool for understanding the intrinsic properties of the nanostructures. In order to understand the light-matter interactions in the near field regime using NSOM technique with an excitation of 532 nm (2.33 eV), we selected an isolated single semiconducting AlGaN nanowire (NW) of diameter ~120 nm grown via vapor liquid solid (VLS) mechanism along with metallic Au nanoparticle (NP) catalyst. The role of electronic transitions from different native defect related energy states of AlGaN are discussed in understanding the NSOM images for the semiconducting NW. The effect of strong surface plasmon resonance absorption of excitation laser in the NSOM images for Au NP, involved in the VLS growth mechanism of NWs, is also observed. Keywo