Developing a Synthesis Process for Large‐Scale h‐BN Nanosheets Using Magnetron Sputtering and Heat Annealing

Hexagonal boron nitride (h‐BN) is an extensively investigated 2D material with exceptional quantum effects, which renders it promising for use in next‐generation nanoelectronic devices. However, the synthesis of single‐ or few‐layer h‐BN nanosheets with large‐area single‐crystal structures is extremely challenging. In this article, a new method is presented for synthesizing h‐BN on a Cu substrate via magnetron sputtering and heat annealing. Three samples with different radio‐frequency (RF) power levels are prepared to evaluate the effect of RF power on h‐BN nanosheet synthesis. Under a higher RF power, the B‐to‐N bonding ratio is closer to 1:1 and further reduces the full width at half maximum of X‐Ray photoelectron spectroscopy B1s and N1s narrow spectra. Heating at 1000 °C reveals white domains with 60° facets, which may correspond to the hexagonal honeycomb lattice structure of h‐BN. Cross‐sectional observations show that a layered structure comprising 10–20 layers forms along the Cu interface. The elemental composition ratio and bonding states reveal the presence of equal amounts of N and B as well as a single peak derived from the B–N bond. Meanwhile, the E_2g mode of h‐BN's six‐membered ring structure is indicated at 1364.6 cm⁻¹, thus demonstrating the successful synthesis of an h‐BN film.