Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

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Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C. / Thomsen, Joachim Dahl; Kling, Jens; Mackenzie, David M.A.; Bøggild, Peter; Booth, Timothy J.

In: ACS Nano, Vol. 13, No. 2, 2019, p. 2281-2288.

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

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@article{2ccaa3849a534f4db0818261d2ebbe76,
title = "Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C",
abstract = "We study the oxidation of clean suspended mono- and few-layer graphene in real-time by in situ environmental transmission electron microscopy. At an oxygen pressure below 0.1 mbar we observe anisotropic oxidation in which armchair-oriented hexagonal holes are formed with a sharp edge roughness below 1 nm. At a higher pressure, we observe an increasingly isotropic oxidation, eventually leading to irregular holes at a pressure of 6 mbar. In addition, we find that few-layer flakes are stable against oxidation at temperatures up to at least 1000 °C in the absence of impurities and electron beam-induced defects. These findings show first that the oxidation behavior of mono- and few-layer graphene depends critically on the intrinsic roughness, cleanliness and any imposed roughness or additional reactivity from a supporting substrate; and second, the activation energy for oxidation of pristine suspended few-layer graphene is up to 43 {\%} higher than previously reported for graphite. In addition we have developed a cleaning scheme that results in the near complete removal of hydrocarbon residues over the entire visible sample area. These results have implications for applications of graphene where edge roughness can critically affect the performance of devices, and more generally highlights the surprising (meta)stability of the basal plane of suspended bilayer and thicker graphene towards oxidative environments at high temperature.",
keywords = "Graphene, Oxidation, Reactivity, TEM, Edge roughness",
author = "Thomsen, {Joachim Dahl} and Jens Kling and Mackenzie, {David M.A.} and Peter B{\o}ggild and Booth, {Timothy J.}",
year = "2019",
doi = "10.1021/acsnano.8b08979",
language = "English",
volume = "13",
pages = "2281--2288",
journal = "A C S Nano",
issn = "1936-0851",
publisher = "American Chemical Society",
number = "2",

}

RIS

TY - JOUR

T1 - Oxidation of Suspended Graphene: Etch Dynamics and Stability Beyond 1000 °C

AU - Thomsen, Joachim Dahl

AU - Kling, Jens

AU - Mackenzie, David M.A.

AU - Bøggild, Peter

AU - Booth, Timothy J.

PY - 2019

Y1 - 2019

N2 - We study the oxidation of clean suspended mono- and few-layer graphene in real-time by in situ environmental transmission electron microscopy. At an oxygen pressure below 0.1 mbar we observe anisotropic oxidation in which armchair-oriented hexagonal holes are formed with a sharp edge roughness below 1 nm. At a higher pressure, we observe an increasingly isotropic oxidation, eventually leading to irregular holes at a pressure of 6 mbar. In addition, we find that few-layer flakes are stable against oxidation at temperatures up to at least 1000 °C in the absence of impurities and electron beam-induced defects. These findings show first that the oxidation behavior of mono- and few-layer graphene depends critically on the intrinsic roughness, cleanliness and any imposed roughness or additional reactivity from a supporting substrate; and second, the activation energy for oxidation of pristine suspended few-layer graphene is up to 43 % higher than previously reported for graphite. In addition we have developed a cleaning scheme that results in the near complete removal of hydrocarbon residues over the entire visible sample area. These results have implications for applications of graphene where edge roughness can critically affect the performance of devices, and more generally highlights the surprising (meta)stability of the basal plane of suspended bilayer and thicker graphene towards oxidative environments at high temperature.

AB - We study the oxidation of clean suspended mono- and few-layer graphene in real-time by in situ environmental transmission electron microscopy. At an oxygen pressure below 0.1 mbar we observe anisotropic oxidation in which armchair-oriented hexagonal holes are formed with a sharp edge roughness below 1 nm. At a higher pressure, we observe an increasingly isotropic oxidation, eventually leading to irregular holes at a pressure of 6 mbar. In addition, we find that few-layer flakes are stable against oxidation at temperatures up to at least 1000 °C in the absence of impurities and electron beam-induced defects. These findings show first that the oxidation behavior of mono- and few-layer graphene depends critically on the intrinsic roughness, cleanliness and any imposed roughness or additional reactivity from a supporting substrate; and second, the activation energy for oxidation of pristine suspended few-layer graphene is up to 43 % higher than previously reported for graphite. In addition we have developed a cleaning scheme that results in the near complete removal of hydrocarbon residues over the entire visible sample area. These results have implications for applications of graphene where edge roughness can critically affect the performance of devices, and more generally highlights the surprising (meta)stability of the basal plane of suspended bilayer and thicker graphene towards oxidative environments at high temperature.

KW - Graphene

KW - Oxidation

KW - Reactivity

KW - TEM

KW - Edge roughness

U2 - 10.1021/acsnano.8b08979

DO - 10.1021/acsnano.8b08979

M3 - Journal article

VL - 13

SP - 2281

EP - 2288

JO - A C S Nano

JF - A C S Nano

SN - 1936-0851

IS - 2

ER -