Beyond Gold: Spin‐Coated Ti3C2‐Based MXene Photodetectors

2D transition metal carbides, known as MXenes, are transparent when the samples are thin enough. They are also excellent electrical conductors with metal‐like carrier concentrations. Herein, these characteristics are exploited to replace gold (Au) in GaAs photodetectors. By simply spin‐coating trans...

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Bibliographic Details
Published in:Advanced materials (Weinheim) 2019-10, Vol.31 (43), p.n/a
Main Authors: Montazeri, Kiana, Currie, Marc, Verger, Louisiane, Dianat, Pouya, Barsoum, Michel W., Nabet, Bahram
Format: Article
Language:English
Subjects:
Acetone
Carrier density
Chemical Sciences
Coated electrodes
Conductors
Dark current
Electric conductors
Electric contacts
Electric fields
Gallium arsenide
Gold
Integrated circuits
Lidar
Material chemistry
Materials science
Metal carbides
metal–semiconductor–metal
MXene
MXenes
Nanosecond response
photodetectors
Photometers
Photonics
Photoresists
Schottky contacts
semiconductors
Transition metals
work‐function
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Summary:2D transition metal carbides, known as MXenes, are transparent when the samples are thin enough. They are also excellent electrical conductors with metal‐like carrier concentrations. Herein, these characteristics are exploited to replace gold (Au) in GaAs photodetectors. By simply spin‐coating transparent Ti3C2‐based MXene electrodes from aqueous suspensions onto GaAs patterned with a photoresist and lifted off with acetone, photodetectors that outperform more standard Au electrodes are fabricated. Both the Au‐ and MXene‐based devices show rectifying contacts with comparable Schottky barrier heights and internal electric fields. The latter, however, exhibit significantly higher responsivities and quantum efficiencies, with similar dark currents, hence showing better dynamic range and detectivity, and similar sub‐nanosecond response speeds compared to the Au‐based devices. The simple fabrication process is readily integratable into microelectronic, photonic‐integrated circuits and silicon photonics processes, with a wide range of applications from optical sensing to light detection and ranging and telecommunications. Ti3C2‐based MXene contacts—spin‐coated from an aqueous colloidal suspension onto a GaAs substrate—are compared with vacuum‐deposited titanium/gold electrodes for the photodetection of light. Such an MXene‐based device has better detectivity, quantum efficiency, and a higher dynamic range as compared to the conventional Au‐based metal–semiconductor–metal devices.
ISSN:0935-9648
1521-4095
DOI:10.1002/adma.201903271