High-quality hexagonal boron nitride from 2D distillation

TL;DR

This paper introduces a novel, low-cost method for producing high-quality, uniform 2D hexagonal boron nitride through a process called 2D distillation, involving transfer, annealing, and sublimation techniques.

Contribution

It presents a new scheme for synthesizing superior quality 2D h-BN by 2D distillation, surpassing traditional CVD methods in quality and uniformity.

Findings

Higher quality and more uniform h-BN achieved

Annealing above 1000 K induces 2D distillation process

Method offers a low-cost alternative to CVD production

Abstract

The production of high-quality two-dimensional (2D) materials is essential for the ultimate performance of single layers and their hybrids. Hexagonal boron nitride (h-BN) is foreseen to become the key 2D hybrid and packaging material since it is insulating, tight, flat, transparent and chemically inert, though it is difficult to attain in ultimate quality. Here, a new scheme is reported for producing single layer h-BN that shows higher quality and much more uniformity than material from chemical vapor deposition (CVD). We delaminate CVD h-BN from Rh(111) and transfer it to a clean metal surface. The twisting angle between BN and the new substrate yields metastable moir\'e structures. Annealing above 1000 K leads to 2D distillation, i.e., catalyst-assisted BN sublimation from the edges of the transferred layer and subsequent condensation into superior quality h-BN. This provides a new and low-cost way of high-quality 2D material production remote from CVD instrumentation.