Plasmon-Induced Optical Anisotropy in Hybrid Graphene–Metal Nanoparticle Systems

Abstract

Hybrid plasmonic metal-graphene systems are emerging as a class of optical metamaterials that facilitate strong light-matter interactions and are of potential importance for hot carrier graphene-based light harvesting and active plasmonic applications. Here we use femtosecond pump-probe measurements to study the near-field interaction between graphene and plasmonic gold nanodisk resonators. By selectively probing the plasmon-induced hot carrier dynamics in samples with tailored graphene-gold interfaces, we show that plasmon-induced hot carrier generation in the graphene is dominated by direct photoexcitation with minimal contribution from charge transfer from the gold. The strong near-field interaction manifests as an unexpected and long-lived extrinsic optical anisotropy. The observations are explained by the action of highly localized plasmon-induced hot carriers in the graphene on the subresonant polarizability of the disk resonator. Because localized hot carrier generation in graphene can be exploited to drive electrical currents, plasmonic metal-graphene nanostructures present opportunities for novel hot carrier device concepts.

Harvesting the loss: surface plasmon-based hot electron photodetection

“…In this device, nanoscale plasmonic antennas are sandwiched between two graphene monolayers. Surface plasmons enhance the photocurrent in two ways: by transferring hot electrons generated from plasmon decay in the antenna and by enhancing the near-field and direct electron-hole pair generation in graphene [139,146]. The contribution of direct photoexcitation and hot carrier injection was also investigated by femtosecond pump-probe measurements [146].…”

“…Surface plasmons enhance the photocurrent in two ways: by transferring hot electrons generated from plasmon decay in the antenna and by enhancing the near-field and direct electron-hole pair generation in graphene [139,146]. The contribution of direct photoexcitation and hot carrier injection was also investigated by femtosecond pump-probe measurements [146]. In addition, MoS 2 has also been used for extracting hot electrons generated from plasmonic nanostrucutres [42,144,145].…”

Programming the assembly of gold nanoparticles on graphene oxide sheets using DNA

“…This effective purification method has been reported by others to separate functionalized graphene oxide from small species. 15,21,25,28,29 An agarose gel of our experiment is shown in Fig. 2A.…”

Graphene and Two-Dimensional Materials for Optoelectronic Applications

“…In addition to these efforts, different strategies have been proposed and demonstrated to enhance the light absorption in graphene-based PDs, which include graphene nanostructures [64], chemical doping [65], plasmonic nanostructures in graphene [66] and the integration of graphene into photonic cavities [67,68]. In graphene, enhancement factors of 15 have been achieved using plasmonic nanostructures [69].…”