Surface and volume plasmons in metallic nanospheres in semiclassical RPA-type approach; near-field coupling of surface plasmons with semiconductor substrate

TL;DR

This paper develops an analytical semiclassical RPA approach to describe surface and volume plasmons in large metallic nanospheres, analyzing their spectrum, damping, and near-field coupling with semiconductor substrates, aligning with experimental data.

Contribution

It introduces a comprehensive analytical model for plasmon excitations in large nanospheres, including damping mechanisms and substrate coupling effects, which was not previously available.

Findings

Spectrum includes surface and volume plasmons with mutual connections.

Damping channels and resonance shifts are quantitatively evaluated.

Strong near-field energy transfer to semiconductor substrates is confirmed.

Abstract

The random-phase-approximation semiclassical scheme for description of plasmon excitations in large metallic nanospheres, with radius range 10-60 nm, is formulated in an all-analytical version. The spectrum of plasmons is determined including both surface and volume type excitations and their mutual connections. The various channels for damping of surface plasmons are evaluated and the relevant resonance shifts are compared with the experimental data for metallic nanoparticles of different size located in dielectric medium or on the semiconductor substrate. The strong enhancement of energy transfer from the surface plasmon oscillations to the substrate semiconductor is explained in the regime of a near-field coupling in agreement with recent experimental observations for metallically nanomodified photo-diode systems.