Large-Area Growth of High Quality Hexagonal Boron Nitride Chemical Vapor Deposition and Its Applications

Abstract

Large-scale growth of high-quality hexagonal boron nitride (h-BN) has been a challenge in two-dimensional (2D)-material-based electronicsbecause 2D insulating dielectric layers are required as dielectric substrates and/or encapsulation layers in electronic devices with graphene or transition metal dichalcogenides. In this presentation, I demonstratewafer-scale and wrinkle-free epitaxial growth of multi-layer h-BN on a sapphire substrate by using high-temperature and low-pressure chemical vapor deposition. Microscopic and spectroscopic investigations and theoretical calculations reveal that synthesized h-BN has a single rotational orientation with Bernal stacking order. A facile method for transferring h-BN onto other target substrates weredeveloped, which provides the opportunity for using h-BN as a substrate in practical electronic circuits. A graphene field effect transistor fabricated on our h-BN sheets shows highly improved carrier mobility, because the ultra-flatness of the h-BN surface can reduce the substrate-induced degradation of the carrier mobility of 2D materials.Afterwards, I show some potential applications of h-BN for a shell layer capping Au nanoparticles in surface-enhance Raman scattering, an encapsulation (or passivation) layer to protect unstable transition metal dichalcogenides (TMDs), and a proton exchange membrane to replace the Nafion film in a polymer electrolyte membrane (PEM) fuel cell.