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

摘要

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