Large-Area Orientation-Controlled Growth of Hexagonal Boron Nitride on Liquid Copper

Two-dimensional semiconductors have great potential in applications of high-performance electrical and optoelectrical devices. Many efforts have been made to meet the challenge of reducing charge scattering between semiconducting and dielectric layers. Hexagonal boron nitride (h-BN) with a large band gap and a flat surface is thus an ideal dielectric layer for addressing this particular requirement. Therefore, preparing high-quality h-BN is an important topic in the electronic industry. In this work, two-opposite orientation growth modes of h-BN domains on liquid Cu are discovered. Comprehensive characterizations verify this anti-orientation feature of the as-grown domains and the grain boundary-free nature in the merged domains with the same orientation. The orientation-controlled h-BN domain growth is achieved by tuning the growth temperature and H2 and Ar flow rates, where the proportion of 0 degrees-orientation domains is modulated in a wide range from similar to 54.4 to 75%. Furthermore, based on the controllable growth of oriented h-BN, centimeter-sized h-BN films with high quality are produced.