Oxygen intercalation in PVD graphene grown on copper substrates: A decoupling approach

Abstract

We investigate the intercalation process of oxygen in-between a PVD-grown graphene layer and different copper substrates as a methodology for reducing the substrate-layer interaction. This growth method leads to an extended defect-free graphene layer that strongly couples with the substrate. We have found, by means of X-ray photoelectron spectroscopy, that after oxygen exposure at different temperatures, ranging from 280 °C to 550 °C, oxygen intercalates at the interface of graphene grown on Cu foil at an optimal temperature of 500 °C. The low energy electron diffraction technique confirms the adsorption of an atomic oxygen adlayer on top of the Cu surface and below graphene after oxygen exposure at elevated temperature, but no oxidation of the substrate is induced. The emergence of the 2D Raman peak, quenched by the large interaction with the substrate, reveals that the intercalation process induces a structural undoing. As suggested by atomic force microscopy, the oxygen intercalation does not change significantly the surface morphology. Moreover, theoretical simulations provide further insights into the electronic and structural undoing process. This protocol opens the door to an efficient methodology to weaken the graphene-substrate interaction for a more efficient transfer to arbitrary surfaces.

Acrylates Polymerization on Covalent Plasma-Assisted Functionalized Graphene: A Route to Synthesize Hybrid Functional Materials

“…Figure a,b shows the C 1s and O 1s core-level spectra evolution, respectively, obtained from the samples after each stage; from top to bottom: pristine HOPG, HOPG sample after p -AP functionalization (HOPG/ p -AP), and HOPG samples after the two polymerization processes (HOPG/ p -AP/L-PHEA and HOPG/ p -AP/H-PHEA). The C 1s core level (Figure a, upper spectrum) of the pristine HOPG shows a single component at 284.0 eV that can be assigned to the sp 2 lattice of graphite. − After p -AP functionalization, a new component at 284.9 eV is observed. This one is ascribed to the sp 3 hybridization of graphite carbon with low intensity in comparison with the sp 2 signal, as expected, considering the contribution of the bulk HOPG .…”

“…The C 1s core level ( Figure 3 a, upper spectrum) of the pristine HOPG shows a single component at 284.0 eV that can be assigned to the sp 2 lattice of graphite. 53 − 55 After p -AP functionalization, a new component at 284.9 eV is observed. This one is ascribed to the sp 3 hybridization of graphite carbon with low intensity in comparison with the sp 2 signal, as expected, considering the contribution of the bulk HOPG.…”

LiCl Photodissociation on Graphene: A Photochemical Approach to Lithium Intercalation

“…Graphene (Gr) has been extensively studied over the past decade, and there is a significant amount of works regarding the intercalation of small molecules or atoms in graphitic-like nanostructures. − In particular, the intercalation of alkali metals under epitaxial graphene has been widely studied − since it is a possible route to tailor the graphene band structure and doping level. Among alkali metals, lithium is especially interesting since, in addition to its capability to engineer graphene doping, − it bears direct technological applications for graphene-based lithium-ion batteries. − In that context, several strategies have appeared focusing on obtaining lithium-intercalated graphene as an anode material by chemical methodologies .…”