Photocurrent enhancement of graphene photodetectors by photon tunneling of light into surface plasmons

Alireza Maleki, Benjamin P. Cumming, Min Gu, James E. Downes, David W. Coutts, Judith M. Dawes

Research output: Contribution to journalArticleResearchpeer-review

Abstract

We demonstrate that surface plasmon resonances excited by photon tunneling through an adjacent dielectric medium enhance the photocurrent detected by a graphene photodetector. The device is created by overlaying a graphene sheet over an etched gap in a gold film deposited on glass. The detected photocurrents are compared for five different excitation wavelengths, ranging from λ0 = 570 nm to λ0 = 730 nm. Although the device is not optimized, the photocurrent excited with incident p-polarized light (which excites resonant surface plasmons) is significantly amplified in comparison with that for s-polarized light (without surface plasmon resonances). We observe that the photocurrent is greater for shorter wavelengths (for both s- and p-polarizations) with increased photothermal current. Position-dependent Raman spectroscopic analysis of the optically-excited graphene photodetector indicates the presence of charge carriers in the graphene near the metallic edge. In addition, we show that the polarity of the photocurrent reverses across the gap as the incident light spot moves across the gap. Graphene-based photodetectors offer a simple architecture which can be fabricated on dielectric waveguides to exploit the plasmonic photocurrent enhancement of the evanescent field. Applications for these devices include photodetection, optical sensing and direct plasmonic detection.

LanguageEnglish
Article number105001
Pages1-8
Number of pages8
JournalJournal of Optics (United Kingdom)
Volume19
Issue number10
DOIs
Publication statusPublished - 18 Sep 2017

Fingerprint

Plasmons
Graphite
Photodetectors
Photocurrents
plasmons
Graphene
photocurrents
photometers
graphene
Photons
augmentation
photons
Surface plasmon resonance
Light polarization
surface plasmon resonance
polarized light
Evanescent fields
Wavelength
Dielectric waveguides
Spectroscopic analysis

Keywords

  • grapheme
  • photodetectors
  • surface plasmons

Cite this

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abstract = "We demonstrate that surface plasmon resonances excited by photon tunneling through an adjacent dielectric medium enhance the photocurrent detected by a graphene photodetector. The device is created by overlaying a graphene sheet over an etched gap in a gold film deposited on glass. The detected photocurrents are compared for five different excitation wavelengths, ranging from λ0 = 570 nm to λ0 = 730 nm. Although the device is not optimized, the photocurrent excited with incident p-polarized light (which excites resonant surface plasmons) is significantly amplified in comparison with that for s-polarized light (without surface plasmon resonances). We observe that the photocurrent is greater for shorter wavelengths (for both s- and p-polarizations) with increased photothermal current. Position-dependent Raman spectroscopic analysis of the optically-excited graphene photodetector indicates the presence of charge carriers in the graphene near the metallic edge. In addition, we show that the polarity of the photocurrent reverses across the gap as the incident light spot moves across the gap. Graphene-based photodetectors offer a simple architecture which can be fabricated on dielectric waveguides to exploit the plasmonic photocurrent enhancement of the evanescent field. Applications for these devices include photodetection, optical sensing and direct plasmonic detection.",
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Photocurrent enhancement of graphene photodetectors by photon tunneling of light into surface plasmons. / Maleki, Alireza; Cumming, Benjamin P.; Gu, Min; Downes, James E.; Coutts, David W.; Dawes, Judith M.

In: Journal of Optics (United Kingdom), Vol. 19, No. 10, 105001, 18.09.2017, p. 1-8.

Research output: Contribution to journalArticleResearchpeer-review

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