Interlayer Charge Transfer and Photodetection Efficiency of Graphene-Transition-Metal-Dichalcogenide Heterostructures

Parappurath, A and Mitra, S and Singh, G and Gill, NK and Ahmed, T and Sai, TP and Watanabe, K and Taniguchi, T and Ghosh, A (2022) Interlayer Charge Transfer and Photodetection Efficiency of Graphene-Transition-Metal-Dichalcogenide Heterostructures. In: Physical Review Applied, 17 (6).

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Abstract

Graphene and transition-metal-dichalcogenide- (TMD) based van der Waals heterostructures in field-effect-transistor (FET) architecture exhibits extremely high sensitivity to optical radiation due to transit and physical separation of the photogenerated carriers across the heterointerface. Both the sensitivity and speed of these detectors depend on the kinetics of charge transfer, but their interdependency at room temperature (T), where these detectors would be most useful, remains largely unexplored. Here we systematically measure the T dependence of the magnitude (gain) and timescale (bandwidth) of photoresponse in graphene-TMD heterostructures well up to the room T. The gain-bandwidth product is found to be strongly dependent on the power of optical illumination and increases with decreasing power (P), becoming as large as 1MHz in the low-P limit. We find that thermally activated back transfer of charge from graphene to the TMD determines the response time of the detector at higher temperatures under continuous illumination. Our experiment reveals the impact of charge-transfer pathways on the performance in a broad class of graphene-TMD detectors.

Item Type:	Journal Article
Publication:	Physical Review Applied
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to the American Physical Society.
Keywords:	Bandwidth; Charge transfer; Field effect transistors; Graphene transistors; Transition metals; Van der Waals forces, Charge transfer efficiency; Field-effect transistor; High sensitivity; In-field; Optical radiations; Photo-detection efficiencies; Power; Transistor architecture; Transition metal dichalcogenides (TMD); Van der Waal, Graphene
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering Division of Physical & Mathematical Sciences > Physics
Date Deposited:	28 Jul 2022 05:22
Last Modified:	28 Jul 2022 05:22
URI:	https://eprints.iisc.ac.in/id/eprint/75009

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