Direct synthesis of single-crystal bilayer graphene on dielectric substrate

TL;DR

This paper presents a novel method for directly growing high-quality, single-crystalline bilayer graphene on various dielectric substrates using a homo-epitaxial growth technique with seeding layers and remote catalysis, enabling high mobility devices.

Contribution

The work introduces a new approach for direct synthesis of single-crystalline bilayer graphene on dielectrics, overcoming previous quality and control challenges.

Findings

Single-crystalline bilayer graphene grown on dielectrics confirmed by TEM.

Carrier mobility of up to 2297 cm²/Vs in FETs on the grown BLG.

Comparable quality of as-grown BLG with CVD-grown graphene on metals.

Abstract

The growth of high-quality Bernal-stacked bilayer graphene (BLG) directly on dielectric substrates is crucial for electronic and optoelectronic applications, but there are still challenges such as poor quality, uncontrollable thickness and polycrystalline films. In this work, a novel method to grow high-quality and single-crystalline BLG directly on various dielectric substrates (SiO2/Si, sapphire, and quartz) was demonstrated. Single-crystalline monolayer graphene was applied as a seeding layer to facilitate the homo-epitaxial synthesis of single-crystalline BLG directly on insulating substrates. The Cu nano-powders (Cu NPs) with nanostructure and high surface-area were used as the remote catalysis to provide long-lasting catalytic activity during the graphene growth. The TEM results confirm the single-crystalline nature of the BLG domains, which validates the superiority of the homo-epitaxial growth technique. The as-grown BLG show comparable quality with the CVD-grown BLG on metal surface. Field-effect transistors directly fabricated on the as-grown BLG/SiO2/Si showed a room temperature carrier mobility as high as 2297cm2/Vs.