Investigating photoresponsivity of graphene-silver hybrid nanomaterials in the ultraviolet

Abstract

Paper published as part of the special topic on Emerging Directions in Plasmonics Note: This paper is part of the JCP Special Topic on Emerging Directions in Plasmonics.

Engineering sensitivity and spectral range of photodetection in van der Waals materials and hybrids

“…Photodetection in the Gr/silvernanoparticle hybrid arises from a combination of photovoltaic, photo-thermoelectric or bolometric processes which work in tandem and the highest responsivity obtained was 3.2 A W −1 between 330 nm and 450 nm. Interestingly, a responsivity of 14.5 A W −1 was observed at 280 nm [31]. This is due to large DoS around the M-point of the Brillouin zone of Gr, and is also aided by the strong disorder induced in Gr through ruptures arising from the transfer process which gives rise to a large number of potential traps.…”

“…The confinement of the EM field can be changed by changing the size and shape of the metal nanoparticles. In figure 1(c), the EM field at the junction of two Ag nanoparticles kept 0.34 nm apart is enhanced up to 10 6 times enhancement [30,31].…”

“…This results in ∼60% absorption of light, as shown through electric field simulations in figure 1(b). Another way to enhance the electric field is to utilize plasmonic nanostructures near the contacts [12] or even sandwich a sheet of Gr between plasmonic nanoparticles [30,31] (see figure 1(c)). Plasmonic oscillations from these nanostructures enhance the local electric field at the p-n junction formed at the interface.…”

“…Sensitization by metallic nanoparticles, allows the photoresponse to be enhanced as well as engineered for a specific spectral range. Responsivity of 2 A W −1 was observed through plasmonic coupling of Gr with metal nanoparticle dimers [31]. The photodetector was designed such that a CVD grown Gr layer lies in between two layers of Ag nanoparticles.…”

Characterization of monolayer WSe2 sandwiched in a hetero-plasmonic dimer

“…The local electromagnetic field at the junction of the sub-nm spaced dimers increased dramatically, thereby resulting in the most sensitive graphene-plasmonic hybrid photodetector reported to date. Such an architecture signifies the tremendous promise of integrating plasmonics with atomically thin materials, especially TMDCs, in nanoelectronics and nanophotonic applications [15][16][17][18][19]44], arising due to the direct bandgap of TMDC monolayers in the visible region.…”