Boron nitride substrates for high-quality graphene electronics

TL;DR

This paper demonstrates that using hexagonal boron nitride as a substrate significantly improves the electronic quality of graphene devices, approaching suspended device performance while maintaining substrate support.

Contribution

The authors develop a mechanical transfer method to fabricate high-quality graphene devices on h-BN substrates, achieving enhanced mobility and reduced disorder compared to SiO2 substrates.

Findings

Increased mobility of graphene on h-BN

Reduced carrier inhomogeneity on h-BN

Lower intrinsic doping levels on h-BN

Abstract

Graphene devices on standard SiO2 substrates are highly disordered, exhibiting characteristics far inferior to the expected intrinsic properties of graphene[1-12]. While suspending graphene above the substrate yields substantial improvement in device quality[13,14], this geometry imposes severe limitations on device architecture and functionality. Realization of suspended-like sample quality in a substrate supported geometry is essential to the future progress of graphene technology. In this Letter, we report the fabrication and characterization of high quality exfoliated mono- and bilayer graphene (MLG and BLG) devices on single crystal hexagonal boron nitride (h-BN) substrates, by a mechanical transfer process. Variable-temperature magnetotransport measurements demonstrate that graphene devices on h-BN exhibit enhanced mobility, reduced carrier inhomogeneity, and reduced intrinsic doping in comparison with SiO2-supported devices. The ability to assemble crystalline layered materials in a controlled way sets the stage for new advancements in graphene electronics and enables realization of more complex graphene heterostructres.