Exceptionally large migration length of carbon and topographically-facilitated self-limiting molecular beam epitaxial growth of graphene on hexagonal boron nitride

Abstract

We demonstrate growth of single-layer graphene (SLG) on hexagonal boron nitride (h-BN) by molecular beam epitaxy (MBE), only limited in area by the finite size of the h-BN flakes. Using atomic force microscopy and micro-Raman spectroscopy, we show that for growth over a wide range of temperatures (500• C -1000• C) the deposited carbon atoms spill off the edge of the h-BN flakes. We attribute this spillage to the very high mobility of the carbon atoms on the BN basal plane, consistent with van der Waals MBE. The h-BN flakes vary in size from 30 µm to 100 µm, thus demonstrating that the migration length of carbon atoms on h-BN is greater than 100 µm. When sufficient carbon is supplied to compensate for this loss, which is largely due to this fast migration of the carbon atoms to and off the edges of the h-BN flake, we find that the best growth temperature for MBE SLG on h-BN is ∼950• C. Self-limiting graphene growth appears to be facilitated by topographic h-BN surface features: We have thereby grown MBE self-limited SLG on an h-BN ridge. This opens up future avenues for precisely tailored fabrication of nano-and hetero-structures on pre-patterned h-BN surfaces for device applications.

An atomic carbon source for high temperature molecular beam epitaxy of graphene

“…The growth of graphene by molecular beam epitaxy (MBE) is also attracting much attention and has been intensively investigated using both gaseous and solid sublimation sources for carbon 5 – 47 . During the last 7 years graphene layers have been successfully grown by MBE with both types of carbon sources with similar deposition rates and the discussion about the optimum design of MBE source for carbon is still ongoing.…”

In situ growth of graphene on hexagonal boron nitride for electronic transport applications

“…Unlike on copper, the growth is not selflimited on h-BN and does not guarantee a uniform monolayer film thickness. Although the observation of restricted monolayer growth on an h-BN ridge in MBE 38 is promising, customizing the number of layers is so far out of reach. Besides CVD and MBE, certain efforts have to be made to evaluate the efficiency of other exiting approaches (e.g., bottom-up synthesis using polycyclic aromatic hydrocarbons) or developing novel modalities in in situ growing graphene on h-BN in the future.…”

Insight on Thermally Activated Hydrocarbon Dehydrogenation on the Pt3Ni(111) Surface: From Adsorbed Hydrocarbons up to Graphene Formation

“…The epitaxial growth of graphene (Gr) on metal substrates continues to attract a considerable interest, − because it allows the obtainment of large-scale samples with high crystalline quality.…”