Related papers: Scanning Raman spectroscopy of graphene antidot la…
We explain the robust p-type doping observed for quasi-free standing graphene on hexagonal silicon carbide by the spontaneous polarization of the substrate. This mechanism is based on a bulk property of SiC, unavoidable for any hexagonal…
Avoiding charge density variations and impurities in graphene is vital for high-quality graphene-based devices. Here, we demonstrate an optical method using Raman 2D peak-split to monitor charge density variations in the range 1-25e10 cm-2.…
We report a confocal Raman study on edges of single layer graphene. It is found that edge orientations could be identified by G mode besides D mode. We observe that G mode at edges of single layer graphene exhibits polar behaviors and…
We achieve fine tuning of graphene effective doping by applying ultrahigh pressures (> 10 GPa) using Atomic Force Microscopy (AFM) diamond tips. Specific areas in graphene flakes are irreversibly flattened against a SiO2 substrate. Our work…
Nanometer-scale graphene objects are attracting much research interest because of newly emerging properties originating from quantum confinement effects. We present Raman spectroscopy studies of graphene nanoribbons (GNRs) which are known…
We use first-principles density-functional calculations to determine the frequency shift of the A$'_1$-${\bf K}$ phonon (Raman D band) in monolayer graphene, as a function of the charge doping. A detailed DFT study on the electron-phonon…
Here we use pristine graphene samples in order to analyze how the Raman peaks intensity, measured at 2.4 eV and 1.96 eV excitation energy, changes with the amount of doping. The use of pristine graphene allows investigating the intensity…
Ab-initio calculations have been performed to study the geometry and electronic structure of boron (B) and nitrogen (N) doped graphene sheet. The effect of doping has been investigated by varying the concentrations of dopants from 2 % (one…
Raman spectroscopy is one of the widely used methods in the analysis of various samples including carbon-based materials. This study aimed to identify the number of layers and defects in graphene using micro-Raman spectroscopy. More…
The Raman active G mode in graphene exhibits strong coupling to electrons, yet the comprehensive treatment of this interaction in the calculation of its temperature-dependent Raman spectrum remains incomplete. In this study, we calculate…
Raman spectroscopy, a fast and nondestructive imaging method, can be used to monitor the doping level in graphene devices. We fabricated chemical vapor deposition (CVD) grown graphene on atomically flat hexagonal boron nitride (hBN) flakes…
We present an analysis of deep-UV Raman measurements of graphite, graphene and carbon nanotubes. For excitation energies above the strong optical absorption peak at the $M$ point in the Brillouin zone ($\approx 4.7\,\text{eV}$), we…
Graphene is an ideal platform to study the coherence of quantum interference pathways by tuning doping or laser excitation energy. The latter produces a Raman excitation profile that provides direct insight into the lifetimes of…
We demonstrate that it is possible to mechanically exfoliate graphene under ultra high vacuum conditions on the atomically well defined surface of single crystalline silicon. The flakes are several hundred nanometers in lateral size and…
We introduce graphene antidot lattice waveguides: nanostructured graphene where a region of pristine graphene is sandwiched between regions of graphene antidot lattices. The band gap in the surrounding antidot lattices enable localized…
We study graphene antidot lattices -- superlattices of perforations (antidots) in a graphene sheet -- using a model that accounts for the phonon-modulation of the $\pi$-electron hopping integrals. We calculate the phonon spectra of selected…
We investigate etched single-layer graphene nanoribbons with different widths ranging from 30 to 130 nm by confocal Raman spectroscopy. We show that the D-line intensity only depends on the edge-region of the nanoribbon and that…
In monolayer graphene, substitutional doping during growth can be used to alter its electronic properties. We used scanning tunneling microscopy (STM), Raman spectroscopy, x-ray spectroscopy, and first principles calculations to…
Twisted bilayer graphene (tBLG) devices with ion gel gate dielectrics are studied using Raman spectroscopy in the twist angle regime where a resonantly enhanced G band can be observed. We observe prominent splitting and intensity quenching…
We show by first-principles calculations that p-doped graphane is a conventional superconductor with a critical temperature (Tc) above the boiling point of liquid nitrogen. The unique strength of the chemical bonds between carbon atoms and…