Inhibited exciton spontaneous emission in InGaAs/GaAs quantum well by the phase-related scattering field of gold nanoparticles

Abstract

We have obtained long lifetime exciton emission in an InGaAs/GaAs quantum well (QW) when the QW film is transferred onto a silicon substrate covered by Au nanoparticles. It is found that the exciton lifetime increases from 0.301 ± 0.003 ns for the as-grown QW sample to 88 ± 6 ns for a QW film with Au nanoparticles, i.e., the spontaneous decay rate is inhibited with a factor of 1/300. The experimental condition of observing long lifetime excitons is very sensitive to the separation distance z between the QW and Au nanoparticles because phase-related scattering field mainly occurs at kz ∼1, where k is the wave vector. A classical dipole oscillator dynamic equation driven by the scattering field of Au nanoparticles can be employed to elucidate the experimental results.