First-Principles Study of the Ga₂O₃/Metal Interface by Inserting a Boron Nitride Monolayer

The wide band gap semiconductor Ga₂O₃ has been well studied in terms of the Schottky diodes. Controlling the Schottky barrier height (SBH) in Ga₂O₃/metal contacts is essential for achieving desirable, high-performance electronic devices. In this article, based on first-principles calculations, we studied the effect of inserting a two-dimensional dielectric layer of hexagonal boron nitride (h-BN) on the SBH of Ga₂O₃/metal. Two sets of interface models with and without the BN interlayer, i.e., Ga₂O₃/Au, Ga₂O₃/BN/Au, Ga₂O₃/Mg, and Ga₂O₃/BN/Mg configurations, were built. As a result, the SBH of high metal work function Au interfaces does not show a significant change after h-BN insertion. In contrast, the SBH of low metal work function Mg interfaces was increased significantly by an h-BN insertion. The reason for this at the atomic level was also explained through electronic structure calculations. They show that inducing a two-dimensional h-BN monolayer can be seen as a transition layer to screen the interface states effectively and weaken the interface interaction greatly. Besides, the effect of the h-BN interlayer on the tunneling barriers was also analyzed. We believe this study will provide insight into improving the performance of wide band gap semiconductor devices with an intercalation structure.