Investigating the role of Cu foil orientation in the growth of large BN films synthesized by reactive RF magnetron sputtering

TL;DR

This study explores how the orientation of copper foil influences the phase and quality of boron nitride films grown via reactive RF magnetron sputtering, highlighting the importance of substrate preparation for scalable hBN production.

Contribution

It demonstrates that copper foil orientation and surface treatment critically affect the phase and morphology of BN films synthesized by reactive sputtering.

Findings

(100) oriented Cu yields mixed cubic and hexagonal BN islands.

(111) oriented Cu produces continuous hexagonal BN films.

Surface treatment of Cu influences BN phase selectivity.

Abstract

Two dimensional materials are an emerging class of materials which is transforming the present day research activity on a phenomenal scale. Hexagonal boron nitride is a wide band gap 2D material which is an excellent substrate for graphene based electronics. To achieve the full potential of hBN scalable and high yield growth procedures are required. Here, we demonstrate the synthesis of hBN by reactive R.F magnetron sputtering over copper foil. Copper foil preparation conditions determines the phase selectivity of BN films. Deposition of hBN on non-electropolished Cu foils with predominant (100) orientation resulted in growth of BN islands with mixed cubic and hexagonal BN phase. On electropolished Cu foils with high symmetry hexagonal (111) surface termination we get growth of continuous hexagonal BN films, while on Cu foils having (100) and (110) orientation with lower symmetry growth of cubic BN films are observed.