Rotationally aligned hexagonal boron nitride on sapphire by high-temperature molecular beam epitaxy

Hexagonal boron nitride (hBN) plays a crucial role in van der Waals heterostructures and devices as a substrate or dielectric layer. In order to move beyond the exfoliation-based fabrication of such devices, it will be necessary to integrate hBN growth into existing, mature epitaxial platforms. In this paper, the authors utilize ultra-high (>1600 degrees Celsius) temperature to realize the MBE synthesis of few-nanometer films of smooth, layered hBN on conventional sapphire substrates. These films additionally demonstrate a rotational alignment to the substrate, demonstrating an influence of the substrate on the growth of two-dimensional crystalline layers.