Details

Autor(en) / Beteiligte

• Daher Mansour, Michel
• Oswald, Jacopo
• Beretta, Davide
• Stiefel, Michael
• Furrer, Roman
• Calame, Michel
• Vuillaume, Dominique

Titel

Nanoscale electronic transport at graphene/pentacene van der Waals interfaces

Ist Teil von

• Nanoscale, 2023-05, Vol.15 (2), p.923-9213

Ort / Verlag

England: Royal Society of Chemistry

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We report a study on the relationship between the structure and electron transport properties of nanoscale graphene/pentacene interfaces. We fabricated graphene/pentacene interfaces from 10 to 30 nm thick needle-like pentacene nanostructures down to two-three layer (2L-3L) dendritic pentacene islands, and we measured their electron transport properties by conductive atomic force microscopy (C-AFM). The energy barrier at the interfaces, i.e. , the energy position of the pentacene highest occupied molecular orbital (HOMO) with respect to the Fermi energy of graphene and the C-AFM metal tip was determined and discussed with an appropriate electron transport model (a double Schottky diode model and a Landauer-Buttiker model, respectively) taking into account the voltage-dependent charge doping of graphene. In both types of samples, the energy barrier at the graphene/pentacene interface is slightly larger than that at the pentacene/metal tip interface, resulting in 0.47-0.55 eV and 0.21-0.34 eV, respectively, for the 10-30 nm thick needle-like pentacene islands, and 0.92-1.44 eV and 0.67-1.05 eV, respectively, for the 2L-3L thick dendritic pentacene nanostructures. We attribute this difference to the molecular organization details of the pentacene/graphene heterostructures, with pentacene molecules lying flat on graphene in the needle-like pentacene nanostructures, while standing upright in the 2L-3L dendritic islands, as observed from Raman spectroscopy. The energetics of graphene/pentacene nanostructures is determined by conductive-AFM measurements combined with analytical models and related to the organization of the pentacene molecules at the interface as deduced from micro-Raman spectroscopy.