High-quality delamination

Science Adv. 1, e1500222 (2015)

Mechanical exfoliation from graphite is known to yield high-quality graphene with impressive electrical performance. Synthesis of graphene on a large scale is needed for its commercialization though, and chemical vapour deposition (CVD) is deemed a suitable route for meeting production demands. However, separation of graphene from the archetypal copper substrate requires contact with a transfer polymer, and the etching of the copper substrate, both of which retard crystal — and electrical — quality. Delamination of CVD graphene is a more attractive approach, with the added advantage that the metal substrate can be re-used for subsequent growth cycles, but has to date resulted in samples with poorer electrical properties than exfoliated ones. Now, Luca Banszerus et al. report a delamination approach utilizing the strong van der Waals interactions between graphene and hexagonal boron nitride (hBN) to lift graphene from the copper substrate, removing the need for crystal-degrading chemical steps. The resultant hBN/graphene heterostructure displays mobilities up to 350,000 cm² V⁻¹ s⁻¹, comparable to exfoliated graphene.