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

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 metalenvironment 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 decreases with the reduction of the electron effective mass slowly than the efficiency of VPE and SPE is more efficient that VPE for small particles, large discontinuity in effective mass and not too high photon energies. Nanoparticle size when SPE is more efficient than VPE is found to be tens of nm or less.