122 research outputs found
Wafer-scale integration of graphene for waveguide-integrated optoelectronics
As the focus of graphene research shifts from fundamental physics to applications, the scalability and reproducibility of experimental results become ever more important. Graphene has been proposed as an enabling material for the continuing growth of the telecommunications industry due to its applications in optoelectronics; however, the extent of its adoption will depend on the possibility to maintain the high intrinsic quality of graphene when processing it using the industry-standard approaches. We look at the challenges of scalable graphene integration and the opportunities presented by the recent technological advances
The Influence of Graphene Curvature on Hydrogen Adsorption: Towards Hydrogen Storage Devices
The ability of atomic hydrogen to chemisorb on graphene makes the latter a
promising material for hydrogen storage. Based on scanning tunneling microscopy
techniques, we report on site-selective adsorption of atomic hydrogen on
convexly curved regions of monolayer graphene grown on SiC(0001). This system
exhibits an intrinsic curvature owing to the interaction with the substrate. We
show that at low coverage hydrogen is found on convex areas of the graphene
lattice. No hydrogen is detected on concave regions. These findings are in
agreement with theoretical models which suggest that both binding energy and
adsorption barrier can be tuned by controlling the local curvature of the
graphene lattice. This curvature-dependence combined with the known graphene
flexibility may be exploited for storage and controlled release of hydrogen at
room temperature making it a valuable candidate for the implementation of
hydrogen-storage devices
Stretching graphene using polymeric micro-muscles
The control of strain in two-dimensional materials opens exciting
perspectives for the engineering of their electronic properties. While this
expectation has been validated by artificial-lattice studies, it remains
elusive in the case of atomic lattices. Remarkable results were obtained on
nanobubbles and nano-wrinkles, or using scanning probes; microscale strain
devices were implemented exploiting deformable substrates or external loads.
These devices lack, however, the flexibility required to fully control and
investigate arbitrary strain profiles. Here, we demonstrate a novel approach
making it possible to induce strain in graphene using polymeric micrometric
artificial muscles (MAMs) that contract in a controllable and reversible way
under an electronic stimulus. Our method exploits the mechanical response of
poly-methyl-methacrylate (PMMA) to electron-beam irradiation. Inhomogeneous
anisotropic strain and out-of-plane deformation are demonstrated and studied by
Raman, scanning-electron and atomic-force microscopy. These can all be easily
combined with the present device architecture. The flexibility of the present
method opens new opportunities for the investigation of strain and
nanomechanics in two-dimensional materials
erratum to superlubricity of epitaxial monolayer ws2 on graphene
The article Superlubricity of epitaxial monolayer WS2 on graphene, written by Holger Buch, Antonio Rossi, Stiven Forti, Domenica Convertino, Valentina Tozzini, and Camilla Coletti, was originally published electronically on the publisher's internet portal (currently SpringerLink) on June 18th 2018 without open access. With the author(s)' decision to opt for Open Choice the copyright of the article changed in August 2018 to © The Author(s) 2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/ ), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made. The original article has been corrected
Anisotropic straining of graphene using micropatterned SiN membranes
We use micro-Raman spectroscopy to study strain profiles in graphene
monolayers suspended over SiN membranes micropatterned with holes of
non-circular geometry. We show that a uniform differential pressure load
over elliptical regions of free-standing graphene yields measurable
deviations from hydrostatic strain conventionally observed in
radially-symmetric microbubbles. The top hydrostatic strain
we observe is estimated to be for in
graphene clamped to elliptical SiN holes with axis and .
In the same configuration, we report a splitting of
which is in good agreement with the calculated anisotropy for our device geometry. Our results are consistent with the
most recent reports on the Gr\"uneisen parameters. Perspectives for the
achievement of arbitrary strain configurations by designing suitable SiN holes
and boundary clamping conditions are discussed.Comment: 8 pages, 6 figure (including SI
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