Surface and volume photoemission from metal nano-particles with electron mass discontinuity

TL;DR

This paper compares surface and volume photoemission efficiencies from metal nanoparticles, highlighting the impact of electron effective mass discontinuity and providing analytical formulas for specific cases.

Contribution

It introduces a quantum mechanical approach accounting for electron mass discontinuity and derives formulas for photoemission efficiencies from metal nanoparticles.

Findings

SPE efficiency decreases less than VPE with electron mass reduction.

SPE is more efficient than VPE for small particles with large mass discontinuity.

Nanoparticles smaller than tens of nanometers favor surface photoemission.

Abstract

Quantum efficiencies of surface (SPE) and volume (VPE) photo-emissions from metal nanoparticles are calculated by quantum mechanical perturbation theory and compared with each other. Along with discontinuities in the potential barrier and dielectric function, the discontinuity in electron effective mass on the metal-environment interface is taken into account. General formulas for quantum efficiencies of SPE and VPE are derived. An example of spherical gold particles with rectangular potential barrier on the interface is considered, analytical formulas for quantum efficiencies of SPE and VPE on the red border of photoemission are derived. It is found that the efficiency of SPE is less decreased with the reduction of the electron effective mass than the efficiency of VPE, so SPE is more efficient that VPE for small particles and large discontinuity in effective mass. Nanoparticle size, when SPE is more efficient than VPE, is found to be tens of nm or less.