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Enhancing Carrier Diffusion Length and Quantum Efficiency through Photoinduced Charge Transfer in Layered Graphene-Semiconducting Quantum Dot Devices

Dutta, R and Pradhan, A and Mondal, P and Kakkar, S and Sai, TP and Ghosh, A and Basu, JK (2021) Enhancing Carrier Diffusion Length and Quantum Efficiency through Photoinduced Charge Transfer in Layered Graphene-Semiconducting Quantum Dot Devices. In: ACS Applied Materials and Interfaces, 13 (20). pp. 24295-24303.

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Official URL: https://doi.org/10.1021/acsami.1c04254


Hybrid devices consisting of graphene or transition metal dichalcogenides (TMDs) and semiconductor quantum dots (QDs) were widely studied for potential photodetector and photovoltaic applications, while for photodetector applications, high internal quantum efficiency (IQE) is required for photovoltaic applications and enhanced carrier diffusion length is also desirable. Here, we reported the electrical measurements on hybrid field-effect optoelectronic devices consisting of compact QD monolayer at controlled separations from single-layer graphene, and the structure is characterized by high IQE and large enhancement of minority carrier diffusion length. While the IQE ranges from 10.2 to 18.2 depending on QD-graphene separation, ds, the carrier diffusion length, LD, estimated from scanning photocurrent microscopy (SPCM) measurements, could be enhanced by a factor of 5-8 as compared to that of pristine graphene. IQE and LD could be tuned by varying back gate voltage and controlling the extent of charge separation from the proximal QD layer due to photoexcitation. The obtained IQE values were remarkably high, considering that only a single QD layer was used, and the parameters could be further enhanced in such devices significantly by stacking multiple layers of QDs. Our results could have significant implications for utilizing these hybrid devices as photodetectors and active photovoltaic materials with high efficiency. © 2021 American Chemical Society.

Item Type: Journal Article
Publication: ACS Applied Materials and Interfaces
Publisher: American Chemical Society
Additional Information: The copyright for this article belongs to American Chemical Society.
Keywords: Charge carriers; Charge transfer; Diffusion; Efficiency; Electric field effects; Graphene; Graphene devices; Hybrid materials; Nanocrystals; Photocurrents; Photodetectors; Photons; Semiconductor quantum dots; Separation; Transition metals, Carrier diffusion length; Internal quantum efficiency; Minority carrier diffusion length; Photoinduced charge transfer; Photovoltaic applications; Photovoltaic materials; Scanning photocurrent microscopies; Transition metal dichalcogenides, Quantum efficiency
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 22 Feb 2023 04:16
Last Modified: 22 Feb 2023 04:16
URI: https://eprints.iisc.ac.in/id/eprint/80475

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