Hybrid functional investigation of the interfacial composition of Diamond/c-BN heterointerfaces*

Heterointerfaces of cubic boron (c-BN) nitride with diamond have garnered significant interest in recent years, since both materials are ultra-wide bandgap semiconductors and possess a relatively small lattice mismatch of just 1.4%. This unique combination offers the potential for precise band offset tuning through doping strategies. However, crystalline growth of c-BN on diamond is challenging due to the intrinsic preference of boron nitride for the layered hexagonal phase (h-BN), and there is a limited understanding of the preferred growth and nucleation mechanisms of c-BN. In this work, we address these challenges by employing density-functional theory (DFT) formalism to calculate formation energies of each interfacial composition, aiming to predict the preferred interfacial bonding environment. Additionally, we report band offsets and their dependence on the interfacial composition using fully ab initio methods, with a comparative study between PBE and hybrid functionals. This work sheds light on the interfacial properties of c-BN/diamond heterointerfaces and paves the way for future understanding and implementation of high-quality c-BN on diamond heterointerfaces.