# Van der Waals Photodetector with an Integrated WS2 Light-Harvesting Antenna

## TL;DR

Researchers improved a photodetector's performance by adding a WS2 bilayer that acts as a light-harvesting antenna, boosting responsivity without directly generating electrical current.

## Contribution

A new strategy for photodetection using TMDs as optical antennas is introduced, enhancing responsivity without direct carrier contribution.

## Key findings

- A WS2 bilayer positioned outside the electronic pathway enhances the photoresponse of a Graphene/MoSe2/Graphene photodetector by up to 18 times.
- The enhancement is attributed to energy transfer from WS2 to graphene and MoSe2, not direct carrier excitation.

## 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.