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Hybrid graphene–quantum dot phototransistors with ultrahigh gain

Konstantatos, Gerasimos, Badioli, Michela, Gaudreau, Louis, Osmond, Johann, Bernechea, Maria, de Arquer, F. Pelayo Garcia, Gatti, Fabio and Koppens, Frank H. L. 2012. Hybrid graphene–quantum dot phototransistors with ultrahigh gain. Nature Nanotechnology 7 (6) , pp. 363-368. 10.1038/nnano.2012.60

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Abstract

Graphene is an attractive material for optoelectronics1 and photodetection applications2, 3, 4, 5, 6 because it offers a broad spectral bandwidth and fast response times. However, weak light absorption and the absence of a gain mechanism that can generate multiple charge carriers from one incident photon have limited the responsivity of graphene-based photodetectors to ~10−2 A W−1. Here, we demonstrate a gain of ~108 electrons per photon and a responsivity of ~107 A W−1 in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of colloidal quantum dots. Strong and tunable light absorption in the quantum-dot layer creates electric charges that are transferred to the graphene, where they recirculate many times due to the high charge mobility of graphene and long trapped-charge lifetimes in the quantum-dot layer. The device, with a specific detectivity of 7 × 1013 Jones, benefits from gate-tunable sensitivity and speed, spectral selectivity from the short-wavelength infrared to the visible, and compatibility with current circuit technologies.

Item Type: Article
Date Type: Published Online
Status: Published
Schools: Engineering
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Publisher: Nature Publishing Group
ISSN: 1748-3387
Date of First Compliant Deposit: 11 August 2016
Date of Acceptance: 23 March 2012
Last Modified: 12 Jun 2019 03:05
URI: https://orca.cardiff.ac.uk/id/eprint/93768

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