Influence of Metal Deposition on Exciton–Surface Plasmon Polariton Coupling in GaAs/AlAs/GaAs Core–Shell Nanowires Studied with Time-Resolved Cathodoluminescence

Abstract

The coupling of excitons to surface plasmon polaritons (SPPs) in Au- and Al-coated GaAs/AlAs/GaAs core–shell nanowires, possessing diameters of ∼100 nm, was probed using time-resolved cathodoluminescence (CL). Excitons were generated in the metal coated nanowires by injecting a pulsed high-energy electron beam through the thin metal films. The Purcell enhancement factor (<i>F</i>_P) was obtained by direct measurement of changes in the temperature-dependent radiative lifetime caused by the nanowire exciton-SPP coupling and compared with a model that takes into account the dependence of <i>F</i>_P on the distance from the metal film and the thickness of the film covering the GaAs nanowires