Direct Synthesis of Single-Crystalline Bilayer Graphene on Dielectric Substrate

TL;DR

This paper presents a new method to grow high-quality bilayer graphene on insulating materials, which is important for electronic devices.

Contribution

A catalyst-assisted method for direct synthesis of single-crystalline bilayer graphene on dielectric substrates is introduced.

Findings

Single-crystalline bilayer graphene was successfully grown on SiO2/Si, sapphire, and quartz substrates.

The quality of the bilayer graphene is comparable to that grown on metal substrates.

Field-effect transistors on the bilayer graphene showed high room temperature carrier mobility.

Abstract

Direct growth of high-quality, Bernal-stacked bilayer graphene (BLG) on dielectric substrates is crucial for electronic and optoelectronic devices, yet it remains hindered by poor film quality, uncontrollable thickness, and high-density grain boundaries. In this work, a facile, catalyst-assisted method to grow high-quality, single-crystalline BLG directly on dielectric substrates (SiO2/Si, sapphire, and quartz) was demonstrated. A single-crystal monolayer graphene template was first employed as a seed layer to facilitate the homoepitaxial synthesis of single-crystalline BLG directly on insulating substrates. Nanostructure Cu powders were used as the remote catalysis to provide long-lasting catalytic activity during the graphene growth. Transmission electron microscopy confirms the single-crystalline nature of the resulting BLG domains, which validates the superiority of the homoepitaxial growth technique. Raman spectroscopy and electrical measurement results indicate that the quality of the as-grown BLG is comparable to that on metal substrate surfaces. Field-effect transistors fabricated directly on the as-grown BLG/SiO2/Si showed a room temperature carrier mobility as high as 2297 ± 3 cm2 V−1 s−1, which is comparable to BLG grown on Cu and much higher than that reported on in-sulators.

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