High-Yield Proximity-Induced Chemical Vapor Deposition of Graphene Over Millimeter-Sized Hexagonal Boron Nitride

TL;DR

This paper introduces a transfer-free method to grow high-quality monolayer graphene on hexagonal boron nitride crystals using a catalytic proximity effect with copper, achieving high coverage and improved electronic properties.

Contribution

The study demonstrates a novel proximity-induced chemical vapor deposition technique for graphene on h-BN, enabling large-area, transfer-free growth with superior electronic mobility.

Findings

High-yield, full coverage of graphene on h-BN crystals achieved

Growth rate estimated between 2-5 μm/min

Electronic mobility around 20,000 cm²/(V·s) in in-situ grown graphene

Abstract

We present a transfer-free preparation method for graphene on hexagonal boron nitride (h-BN) crystals by chemical vapor deposition of graphene via a catalytic proximity effect, i.e. activated by a Cu catalyst close-by . We demonstrate the full coverage by monolayer graphene of half-millimeter-sized hexagonal boron nitride crystals exfoliated on a copper foil prior to growth. We demonstrate that the proximity of the copper catalyst ensures high yield with the growth rate estimated between of 2\mu m/min to 5\mu m/min . Optical and electron microscopies together with confocal micro-Raman mapping confirm that graphene covers the top surface of h-BN crystals that we attribute to be a lateral growth from the supporting catalytic copper substrate. Structural and electron transport characterization of the in-situ grown graphene present an electronic mobility of about 20, 000cm2/(V.s). Comparison with graphene/h-BN stacks obtained by manual transferring of similar CVD graphene onto h-BN, confirms the better neutrality reached by the self-assembled structures.