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.

Room-temperature photoconductivity in superconducting tungsten meander wires

“…Particularly, the observed current increases due to enhancement of the extra charge carrier generation by absorbing photons under the illumination of laser light, defined with positive photoconductivity (PP) mechanism. [47][48][49][50][51] The most well-defined fact of PP origin in the optical performance of a material is related to the presence of energy band gap between the valence and conduction band, wherein the charge carriers are excited due to the higher incident energy with the illumination of laser light than the energy band gap of the material. The observed PP mechanism in most of the nanostructures also is originated/enhanced through the surface plasmonic effects, [52][53][54][55][56][57][58] in which the laser light-induced excited or generated charge carriers collectively rise with the increment of the photocurrent.…”