Negative Differential Photoconductance as a Signature of Nonradiative Energy Transfer in van der Waals Heterojunction

Dandu, M and Gupta, G and Majumdar, K (2021) Negative Differential Photoconductance as a Signature of Nonradiative Energy Transfer in van der Waals Heterojunction. In: ACS Nano .

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Abstract

The physical proximity of layered materials in their van der Waals heterostructures (vdWhs) aids interfacial phenomena such as charge transfer (CT) and energy transfer (ET). Besides providing fundamental insights, CT and ET also offer routes to engineer optoelectronic properties of vdWhs. For example, harnessing ET in vdWhs can help to overcome the limitations of optical absorption imposed by the ultra-thin nature of layered materials and thus provide an opportunity for in situ enhancement of quantum efficiency for light-harvesting and sensing applications. While several spectroscopic studies on vdWhs probed the dynamics of CT and ET, the possible contribution of ET in the photocurrent generation remains largely unexplored. In this work, we investigate the role of nonradiative energy transfer (NRET) in the photocurrent through a vertical vdWh of SnSe2/MoS2/TaSe2. We observe an unusual negative differential photoconductance (NDPC) arising from the existence of NRET across the SnSe2/MoS2 junction. Modulation of the NRET-driven NDPC characteristics with optical power results in a striking transition of the photocurrent's power law from a sublinear to a superlinear regime. Our observations reveal the nontrivial influence of ET on the photoresponse of vdWhs, which offer insights to harness ET in synergy with CT for vdWh based next-generation optoelectronics. © 2021 American Chemical Society.

Item Type:	Journal Article
Publication:	ACS Nano
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Energy transfer; Heterojunctions; Layered semiconductors; Light absorption; Photocurrents; Photoluminescence; Selenium compounds; Semiconductor quantum wells; Spectroscopic analysis; Tin compounds; Van der Waals forces, Energy-transfer; Layered material; Negative differential photoconductance; Nonradiative energy transfer; Photoconductance; Physical proximity; Superlinear; Superlinear photocurrent; Van der Waal; Van der waal heterojunction, Charge transfer
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	16 Nov 2021 11:37
Last Modified:	16 Nov 2021 11:37
URI:	http://eprints.iisc.ac.in/id/eprint/70516

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