Photocurrent in plasmonic nanofibers

Abstract

We developed a theory of photoresponse and photocurrent in photonic nanofibers. Photonic nanofiber is a compound system doped with an ensemble of quantum dots and metallic nanoparticles, where they interact with each other via the dipole–dipole interaction. The bound states of the confined probe photons in the nanofiber hybrid are calculated using the transfer matrix method based on Maxwell’s equations. It is found that the density of states of photons in the nanofiber depends on the dipole–dipole interaction coupling. The nonradiative decay rate due to dipole–dipole interaction rates is calculated using the quantum mechanical perturbation theory. An analytical expression of the photoresponse coefficient and the photocurrent is calculated using the density matrix method. We predicted that the quenching in photocurrent is due to the dipole–dipole interaction. Furthermore, we have shown that the photoluminescence quenching increases as the strength of the dipole–dipole coupling increases. We also compared our theory with the experimental results of the photocurrent in a nanofiber doped with Al metallic nanoparticle nanodisks and Ge/Si quantum dots. A good agreement between theory and experiment is found. Our analytical expressions can be used by experimentalists to perform new types of experiments and for inventing new types of nanosensors and nanoswitches.