Hole-doping of mechanically exfoliated graphene by confined hydration layers

Bollmann, Tjeerd Rogier Johannes; Antipina, Liubov Yu.; Temmen, Matthias; Reichling, Michael; Сорокин, Павел Б.

doi:10.1007/s12274-015-0807-x

Cited by 20 publications

(25 citation statements)

References 42 publications

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“…Immediately above the K + ions, graphene is significantly less conductive than over ion-free locations. This result indicates charge transfer from the underlying surface to graphene and is in good agreement with previous studies 15 25 26 27 . Our results shed light on the local distribution of ions on air-cleaved mica and pave the way for controlling the local electronic landscape of graphene.…”

supporting

confidence: 93%

Graphene Visualizes the Ion Distribution on Air-Cleaved Mica

Bampoulis

Sotthewes

Siekman

et al. 2017

Sci Rep

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The distribution of potassium (K+) ions on air-cleaved mica is important in many interfacial phenomena such as crystal growth, self-assembly and charge transfer on mica. However, due to experimental limitations to nondestructively probe single ions and ionic domains, their exact lateral organization is yet unknown. We show, by the use of graphene as an ultra-thin protective coating and scanning probe microscopies, that single potassium ions form ordered structures that are covered by an ice layer. The K+ ions prefer to minimize the number of nearest neighbour K+ ions by forming row-like structures as well as small domains. This trend is a result of repulsive ionic forces between adjacent ions, weakened due to screening by the surrounding water molecules. Using high resolution conductive atomic force microscopy maps, the local conductance of the graphene is measured, revealing a direct correlation between the K+ distribution and the structure of the ice layer. Our results shed light on the local distribution of ions on the air-cleaved mica, solving a long-standing enigma. They also provide a detailed understanding of charge transfer from the ionic domains towards graphene.

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supporting

confidence: 93%

Graphene Visualizes the Ion Distribution on Air-Cleaved Mica

Bampoulis

Sotthewes

Siekman

et al. 2017

Sci Rep

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“…The formation of a fourth water layer was never observed. 33 The fact that we have never observed a fourth water layer indicates that it is energetically unfavorable. This may be a result of dangling OH bonds on the surface of the third layer, induced by the hydrophobicity of graphene.…”

Section: Resultsmentioning

confidence: 80%

Charge Induced Dynamics of Water in a Graphene–Mica Slit Pore

et al. 2017

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We use atomic force microscopy to in situ investigate the dynamic behavior of confined water at the interface between graphene and mica. The graphene is either uncharged, negatively charged, or positively charged. At high humidity, a third water layer will intercalate between graphene and mica. When graphene is negatively charged, the interface fills faster with a complete three layer water film, compared to uncharged graphene. As charged positively, the third water layer dewets the interface, either by evaporation into the ambient or by the formation of three-dimensional droplets under the graphene, on top of the bilayer. Our experimental findings reveal novel phenomena of water at the nanoscale, which are interesting from a fundamental point of view and demonstrate the direct control over the wetting properties of the graphene/water interface.

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“…(d) The relation of free charge carrier density and surface potential difference of graphene with increasing number of confined water layers. Reproduced with permission of Springer from [98].…”

Section: Effects Of Water On the Local Electronic Properties Of Graphenementioning

confidence: 99%

Water on graphene: review of recent progress

et al. 2018

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The sensitivity of graphene to the surrounding environment is given by its π electrons, which are directly exposed to molecules in the ambient. The high sensitivity of graphene to the local environment has shown to be both advantageous but also problematic for graphene-based devices, such as transistors and sensors, where the graphene carrier concentration and mobility change due to ambient humidity variations. In this review, recent progress in understanding the effects of water on different types of graphene, grown epitaxially and quasi-free standing on SiC, by chemical vapour deposition on SiO2, as well as exfoliated flakes, are presented. It is demonstrated that water withdraws electrons from graphene, but the graphene-water interaction highly depends on the thickness, layer stacking, underlying substrate and substrate-induced doping. Moreover, we highlight the importance of clear and unambiguous description of the environmental conditions (i.e. relative humidity) whenever a routine characterisation for carrier concentration and mobility is reported (often presented as a simple figure-of-merit), as these electrical characteristics are highly dependent on the adsorbed molecules and the surrounding environment.

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Hole-doping of mechanically exfoliated graphene by confined hydration layers

Cited by 20 publications

References 42 publications

Graphene Visualizes the Ion Distribution on Air-Cleaved Mica

Graphene Visualizes the Ion Distribution on Air-Cleaved Mica

Charge Induced Dynamics of Water in a Graphene–Mica Slit Pore

Water on graphene: review of recent progress

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