Synthesis of large single-crystal hexagonal boron nitride grains on Cu-Ni alloy

TL;DR

This paper reports a method to grow large single-crystal hexagonal boron nitride grains on Cu-Ni alloy substrates, significantly reducing nucleation density and enabling larger crystal sizes for electronic applications.

Contribution

It introduces a Ni ratio optimization strategy on Cu-Ni alloys to produce large single-crystal h-BN grains, advancing growth control and material quality.

Findings

Nucleation density reduced to 60 per mm2

Single-crystal h-BN grains up to 7,500 um2 achieved

Provides insights into h-BN growth mechanisms

Abstract

Hexagonal boron nitride (h-BN) has attracted significant attention due to its superior properties as well as its potential as an ideal dielectric layer for graphene-based devices. The h-BN films obtained via chemical vapor deposition in earlier reports are always polycrystalline with small grains due to high nucleation density on substrates. Here we report the successful synthesis of large single-crystal h-BN grains on rational designed Cu-Ni alloy foils. It is found that the nucleation density can be greatly reduced to 60 per mm2 by optimizing Ni ratio in substrates. The strategy enables the growth of single-crystal h-BN grains up to 7,500 um2, about 2 orders larger than that in previous reports. This work not only provides valuable information for understanding h-BN nucleation and growth mechanisms, but also gives an effective alternative to exfoliated h-BN as a high-quality dielectric layer for large-scale nano-electronic applications.