Wafer-scale CVD Growth of Monolayer Hexagonal Boron Nitride with Large Domain Size by Cu Foil Enclosure Approach

TL;DR

This paper demonstrates a novel Cu foil enclosure method for growing large, high-quality monolayer hexagonal boron nitride with domain sizes up to 72 micrometers, advancing wafer-scale synthesis techniques.

Contribution

The study introduces a folded Cu enclosure approach that significantly reduces nucleation density and suppresses etching, enabling wafer-scale growth of large-domain h-BN monolayers.

Findings

Largest single crystalline domain size of 72 micrometers achieved

Cu (111) substrate identified as optimal for high-quality h-BN growth

Growth orientation strongly correlated with substrate crystalline facets

Abstract

Chemical vapor deposition synthesis of large domain hexagonal boron nitride (h-BN) with uniform thickness on Cu foils is of great challenge, originating from the extremely high nucleation densities and the reverse hydrogen etching competition reaction. We report herein the successful growth of wafer-scale high-quality h-BN monolayer film with the largest single crystalline domain sizes up to 72 micrometer in edge length using a folded Cu enclosure approach. The highly-confined growth space with this facile and unique approach enables the drastic decrease of nucleation centers together with the effective suppression of hydrogen etching reaction. It is revealed, for the first time, that the orientations of as-grown h-BN monolayers are strongly correlated with the crystalline facets of growth substrates, with the Cu (111) being the best substrate for growing high-quality single crystalline h-BN monolayer, consistent with the density functional theory calculations. The present study offers a practical pathway for growing high-quality h-BN films and deepens the fundamental understanding of h-BN growth process.