Excellent electronic transport in heterostructures of graphene and monoisotopic boron-nitride grown at atmospheric pressure

TL;DR

This paper introduces a scalable atmospheric pressure growth method for high-quality, monoisotopic boron nitride, enabling advanced graphene heterostructures with excellent electronic properties such as quantum Hall states and ballistic transport.

Contribution

It presents a novel atmospheric pressure growth technique for isotopically purified BN, offering a scalable alternative to high-pressure methods for high-quality graphene/BN heterostructures.

Findings

High-quality monoisotopic BN grown at atmospheric pressure

Observation of fractional quantum Hall states in heterostructures

Ballistic transport over ~10 micrometers at low temperatures

Abstract

Hexagonal boron nitride (BN), one of the very few layered insulators, plays a crucial role in 2D materials research. In particular, BN grown with a high pressure technique has proven to be an excellent substrate material for graphene and related 2D materials, but at the same time very hard to replace. Here we report on a method of growth at atmospheric pressure as a true alternative for producing BN for high quality graphene/BN heterostructures. The process is not only more scalable, but also allows to grow isotopically purified BN crystals. We employ Raman spectroscopy, cathodoluminescence, and electronic transport measurements to show the high-quality of such monoisotopic BN and its potential for graphene-based heterostructures. The excellent electronic performance of our heterostructures is demonstrated by well developed fractional quantum Hall states, ballistic transport over distances around $10\,\mathrm{\mu m}$ at low temperatures and electron-phonon scattering limited transport at room temperature.