High-Efficiency Infrared Sensing with Optically Excited Graphene-Transition Metal Dichalcogenide Heterostructures

Kakkar, S and Majumdar, A and Ahmed, T and Parappurath, A and Gill, NK and Watanabe, K and Taniguchi, T and Ghosh, A (2022) High-Efficiency Infrared Sensing with Optically Excited Graphene-Transition Metal Dichalcogenide Heterostructures. In: Small .

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Abstract

Binary van der Waals heterostructures of graphene (Gr) and transition metal dichalcogenide (TMDC) have evolved as a promising candidate for photodetection with very high responsivity due to the separation of photo-excited electron–hole pairs across the interface. The spectral range of optoelectronic response in such hybrids has so far been limited by the optical bandgap of the light absorbing TMDC layer. Here, the bidirectionality of interlayer charge transfer is utilized for detecting sub-band gap photons in Gr-TMDC heterostructures. A Gr/MoSe2 heterostructure sequentially driven by visible and near infra-red (NIR) photons is employed, to demonstrate that NIR induced back transfer of charge allows fast and repeatable detection of the low energy photons (less than the optical band gap of the TMDC layer). This mechanism provides photoresponsivity as high as ≈3000 A W−1 close to the communication wavelength. The experiment provides a new strategy for achieving highly efficient photodetection over a broad range of energies beyond the spectral bandgap with the 2D semiconductor family.

Item Type:	Journal Article
Publication:	Small
Publisher:	John Wiley and Sons Inc
Additional Information:	The copyright for this article belongs to the John Wiley and Sons Inc.
Keywords:	Charge transfer; Energy gap; Graphene; Heterojunctions; Infrared devices; Optical band gaps; Photodetectors; Photons; Van der Waals forces, Dichalcogenides; Higher efficiency; Near infra-red photodetector; Near Infrared; Photo detection; Responsivity; Transition metal dichalcogenides; Transition metal dichalcogenides (TMD); Van der Waal; Van der waal heterostructure, Transition metals
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering Division of Physical & Mathematical Sciences > Physics
Date Deposited:	28 Jul 2022 09:26
Last Modified:	28 Jul 2022 09:26
URI:	https://eprints.iisc.ac.in/id/eprint/75027

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