Publication

Van Der Waals Photodetector with an Integrated Ws<sub>2</sub> Light-harvesting Antenna

2025

Abstract

The responsivity of graphene-based photodetectors can be improved by forming heterostructures with other 2D materials and by further coupling to nanoparticles or quantum dots. In this study, we demonstrate that the photoresponse of a Graphene/MoSe2/Graphene photodetector can be further enhanced by an external WS2 bilayer acting as a light-harvesting antenna. The WS2 bilayer is positioned outside the electronic pathway; thus, it does not directly contribute any photoexcited carriers. However, we observe a responsivity enhancement of up to 18 times, which can be explained by energy transfer from WS2 to graphene and the MoSe2 layer. Harnessing the excitonic properties of transition metal dichalcogenides (TMDs) as optical antennas defines a new strategy for photodetection.

Official source

https://infoscience.epfl.ch/entities/publication/8d98708e-0785-48b3-a767-6df0f0e3b914

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2025

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/8d98708e-0785-48b3-a767-6df0f0e3b914

About this result

Related concepts (32)

Graphene

Graphene (ˈgræfiːn) is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. The name is derived from "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds. Each atom in a graphene sheet is connected to its three nearest neighbors by σ-bonds and a delocalised π-bond, which contributes to a valence band that extends over the whole sheet.

Potential applications of graphene

Potential graphene applications include lightweight, thin, and flexible electric/photonics circuits, solar cells, and various medical, chemical and industrial processes enhanced or enabled by the use of new graphene materials. In 2008, graphene produced by exfoliation was one of the most expensive materials on Earth, with a sample the area of a cross section of a human hair costing more than

1,000 as of April 2008 (about

100,000,000/cm2). Since then, exfoliation procedures have been scaled up, and now companies sell graphene in large quantities.

Quantum dot

Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.

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