Etching of graphene on Ir(111) with molecular oxygen

Schröder, Ulrike A.; Grånäs, Elin; Gerber, Timm; Arman, Mohammad A.; Martínez‐Galera, Antonio J.; Schulte, Karina; Andersen, Jesper N; Knudsen, Jan; Michely, Thomas

doi:10.1016/j.carbon.2015.09.063

Cited by 29 publications

(23 citation statements)

References 59 publications

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“…2a . The temperature we used during oxygen exposure does not allow the etching of graphene, which takes place at higher temperatures even on partially covered iridium 26 . In fact, the intensity of the C 1 s does not show any decrease (etching) during the process, indicating the integrity of the graphene flakes, as reported in Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

“…This shift is not compatible with oxygen intercalation, since that mechanism does not implicate a gradual progressive shift in the binding energy of the C 1 s as in the case of doping. Instead, intercalation causes a peak broadening due to the appearance of a second component arising from O-(2 × 1) intercalated regions 26 , 27 . We thus attribute this shift to reduced n -doping by the graphitic nitrogen due to absorbed oxygen atoms, as we will show later by core level simulations.…”

Section: Resultsmentioning

confidence: 99%

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Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

Scardamaglia

Susi

Struzzi

et al. 2017

Sci Rep

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Carbon nanomaterials’ reactivity towards oxygen is very poor, limiting their potential applications. However, nitrogen doping is an established way to introduce active sites that facilitate interaction with gases. This boosts the materials’ reactivity for bio-/gas sensing and enhances their catalytic performance for the oxygen reduction reaction. Despite this interest, the role of differently bonded nitrogen dopants in the interaction with oxygen is obscured by experimental challenges and has so far resisted clear conclusions. We study the interaction of molecular oxygen with graphene doped via nitrogen plasma by in situ high-resolution synchrotron techniques, supported by density functional theory core level simulations. The interaction leads to oxygen dissociation and the formation of carbon-oxygen single bonds on graphene, along with a band gap opening and a rounding of the Dirac cone. The change of the N 1 s core level signal indicates that graphitic nitrogen is involved in the observed mechanism: the adsorbed oxygen molecule is dissociated and the two O atoms chemisorb with epoxy bonds to the nearest carbon neighbours of the graphitic nitrogen. Our findings help resolve existing controversies and offer compelling new evidence of the ORR pathway.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

Scardamaglia

Susi

Struzzi

et al. 2017

Sci Rep

View full text Add to dashboard Cite

show abstract

“…In particular, by opportune thermal treatments in controlled atmosphere it has been shown that Gr and also other 2D materials of interest can be doped, but some drawbacks arising from the environment can come including stress effects . In addition, it has been shown that for metal substrate Gr etching could be started as well as in the case of harsh thermal treatments of Gr on dielectric substrates . In this context, a role of molecular water has been evidenced and its interaction with substrate is of particular concern in activating or contrasting the doping .…”

Section: Introductionmentioning

confidence: 99%

Graphene‐SiO₂ Interaction from Composites to Doping

Armano

Buscarino

Cannas

et al. 2019

Physica Status Solidi (a)

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An overview of the interaction between monolayer graphene and SiO2 dielectric substrate is reported focusing on the effect this latter has on doping and strain induced by thermal treatments in controlled atmosphere. The disentanglement of strain and doping is highlighted and the comparison with another dielectric substrate of Al2O3 evidences the critical role that the substrate has in the electronic properties of graphene. The reported results pave the way for microelectronic devices based on graphene on dielectrics and for Fermi level tuning in composites of graphene and nanoparticles.

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“…However, to estimate the work function Φ Gr/O/Ir more accurately, we need to understand the loss of graphene due to its reaction with oxygen during intercalation and deintercalation. Loss of graphene during both processes have been observed, showing that as much as 20% of the graphene may be lost during deintercalation but only 1-2% during intercalation 1,53,54 . Hence, for the rest of our discussion we may assume a ≈ 1% graphene loss during oxygen intercalation, from which we estimate that Φ Gr/O/Ir ≈ 5.12 eV; this value will be used to derive the binding energies of the IPS below.…”

Section: Work Function Measurement For Gr/o/irmentioning

confidence: 98%

Excitation and characterization of image potential state electrons on quasi-free-standing graphene

Lin

Sadowski

et al. 2018

Phys. Rev. B

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We investigate the band structure of image potential states in quasi-free-standing graphene (QFG) monolayer islands using angle-resolved two-photon-photoemission spectroscopy (AR-2PPE). Direct probing by low-energy electron diffraction (LEED) shows that QFG is formed following oxygen intercalation into the graphene-Ir(111) interface. Despite the apparent decoupling of the monolayer graphene from the Ir substrate, we find that the binding energy of the n=1 image potential state on these QFG islands increases by 0.17 eV, as compared to the original Gr/Ir(111) interface. We use calculations based on density functional theory to construct an empirical, one-dimensional potential that quantitatively reproduces the image potential state binding energy and links the changes in the interface structure to the shift in energy. Specifically, two factors, arising from the presence of intercalated oxygen adatoms, contribute comparably to this energy shift: a deeper potential well and the increase in the graphene-Ir distance associated with a wider potential well. While image potential states have not been observed previously on QFG by photoemission, our work now demonstrates that they may be strongly excited in a well-defined QFG system produced by oxygen intercalation. This opens an opportunity for studying the surface electron dynamics in QFG systems, beyond those found in typical non-intercalated graphene-on-substrate systems.

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Etching of graphene on Ir(111) with molecular oxygen

Cited by 29 publications

References 59 publications

Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

Graphene‐SiO₂ Interaction from Composites to Doping

Excitation and characterization of image potential state electrons on quasi-free-standing graphene

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Etching of graphene on Ir(111) with molecular oxygen

Cited by 29 publications

References 59 publications

Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

Spectroscopic observation of oxygen dissociation on nitrogen-doped graphene

Graphene‐SiO2 Interaction from Composites to Doping

Excitation and characterization of image potential state electrons on quasi-free-standing graphene

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Product

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Graphene‐SiO₂ Interaction from Composites to Doping