Jump to main content
Jump to site search

Issue 32, 2017
Previous Article Next Article

Morphological imperfections of epitaxial graphene: from a hindrance to the generation of new photo-responses in the visible domain

Author affiliations

Abstract

We report the discovery of remarkable photo-physical phenomena with characteristics unique to epitaxial graphene grown on 6H-SiC (000−1). Surprisingly, the electrical resistance of graphene increases under light illumination in contrast to conventional materials where it normally decreases. The resistance shows logarithmic temperature dependences which may be attributed to an Altshuler–Aronov effect. We show that the photoresistance depends on the frequency of the irradiating light, with three lasers (red, green, and violet) used to demonstrate the phenomenon. The counterintuitive rise of the positive photoresistance may be attributed to a creation of trapped charges upon irradiation. We argue that the origin of the photoresistance is related to the texture formed by the graphene flakes. Photovoltage also exists and increases with light intensity. However, its value saturates quickly with irradiation and does not change with time. The saturation of the photovoltage may be associated with the formation of a quasi-equilibrium state of the excited electrons and holes associated with a charge redistribution between the graphene and SiC substrate. The obtained physical picture is in agreement with the photoresistance measurements: X-ray photoelectron spectrometry “XPS”, atomic force microscopy “AFM”, Raman spectroscopy and the magnetic dependence of photoresistance decay measurements. We also observed non-decaying photoresistance and linear magnetoresistance in magnetic fields up to 1 T. We argue that this is due to topological phases spontaneously induced by persistent current formation within the graphene flake edges by magnetic fields.

Graphical abstract: Morphological imperfections of epitaxial graphene: from a hindrance to the generation of new photo-responses in the visible domain

Back to tab navigation

Supplementary files

Publication details

The article was received on 18 Nov 2016, accepted on 07 May 2017 and first published on 11 May 2017


Article type: Paper
DOI: 10.1039/C6NR08999B
Citation: Nanoscale, 2017,9, 11463-11474
  • Open access: Creative Commons BY license
  •   Request permissions

    Morphological imperfections of epitaxial graphene: from a hindrance to the generation of new photo-responses in the visible domain

    A. Ben Gouider Trabelsi, F. V. Kusmartsev, M. B. Gaifullin, D. M. Forrester, A. Kusmartseva and M. Oueslati, Nanoscale, 2017, 9, 11463
    DOI: 10.1039/C6NR08999B

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements