Claire Mathieu

Epitaxial Graphene on 4H-SiC(0001) Grown under Nitrogen Flux: Evidence of Low Nitrogen Doping and High Charge Transfer

Nitrogen doping of graphene is of great interest for both fundamental research to explore the effect of dopants on a 2D electrical conductor and applications such as lithium storage, composites, and nanoelectronic devices. Here, we report on the modifications of the electronic properties of epitaxial graphene thanks to the introduction, during the growth, of nitrogen-atom substitution in the carbon honeycomb lattice. High-resolution transmission microscopy and low-energy electron microscopy investigations indicate that the nitrogen-doped graphene is uniform at large scale. The substitution of nitrogen atoms in the graphene planes was confirmed by high-resolution X-ray photoelectron spectroscopy, which reveals several atomic configurations for the nitrogen atoms: graphitic-like, pyridine-like, and pyrrolic-like. Angle-resolved photoemission measurements show that the N-doped graphene exhibits large n-type carrier concentrations of 2.6 × 10(13) cm(-2), about 4 times more than what is found for pristine graphene, grown under similar pressure conditions. Our experiments demonstrate that a small amount of dopants (<1%) can significantly tune the electronic properties of graphene by shifting the Dirac cone about 0.3 eV toward higher binding energies with respect to the π band of pristine graphene, which is a key feature for envisioning applications in nanoelectronics.

Large-Area and High-Quality Epitaxial Graphene on Off-Axis SiC Wafers

The growth of large and uniform graphene layers remains very challenging to this day due to the close correlation between the electronic and transport properties and the layer morphology. Here, we report the synthesis of uniform large-scale mono- and bilayers of graphene on off-axis 6H-SiC(0001) substrates. The originality of our approach consists of the fine control of the growth mode of the graphene by precise control of the Si sublimation rate. Moreover, we take advantage of the presence of nanofacets on the off-axis substrate to grow a large and uniform graphene with good long-range order. We believe that our approach represents a significant step toward the scalable synthesis of graphene films with high structural qualities and fine thickness control, in order to develop graphene-based electronic devices.

Observation of the quantum Hall effect in epitaxial graphene on SiC(0001) with oxygen adsorption

In this letter we report on transport measurements of epitaxial graphene on SiC(0001) with oxygen adsorption. In a

Full field electron spectromicroscopy applied to ferroelectric materials

50\times 50 \mu\mathrm{m^2}

Correlation Clustering and Two-edge-connected Augmentation for Planar Graphs

size Hall bar we observe the half-integer quantum Hall effect with a transverse resistance plateau quantized at filling factor around

The bottom-up growth of edge specific graphene nanoribbons.

\nu = 2

From nanographene to monolayer graphene on 6H-SiC(0001) substrate

, an evidence of monolayer graphene. We find low electron concentration of

Polarization dependent chemistry of ferroelectric BaTiO3(001) domains

9\times 10^{11} \textrm{cm}^{-2}

Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate.

and we show that a doping of

Approximating connectivity domination in weighted bounded-genus graphs

10^{13}\textrm{cm}^{-2}