Computational Modeling and Analysis of Diamond/c-BN Heterostructure Interfaces for High Performance Electronic Applications

Diamond/c-BN heterostructures are of particular interest for high-frequency, high-power electronic device applications due to the materials' superior properties, such as ultra-wide bandgaps, high thermal conductivity, high breakdown fields, and high carrier mobility. These diamond/cBN heterostructures have shown potential for creating highly conductive two-dimensional (2D) channels at their interfaces. The interface between the two bulk structures could be a combination of carbon, nitrogen, and boron atoms. However, computational studies to date have assumed a bulk-diamond to bulk-cBN interface. The purpose of this project is to computationally model the interface layer between diamond and c-BN and quantify its structural and electronic properties. To determine the interface, we employed an evolutionary algorithm to search through configuration space where C, B, and N atoms were randomly placed between a diamond(100) slab and a c-BN slab. Given that c-BN is composed of alternating layers of B and N, we considered both the boron-terminated case and the nitrogen-terminated case. We also created examples based on maximizing/minimizing the interatomic distance between different types of atoms. All favorable cases were then relaxed with density functional theory. The most favorable interfaces had a consistently mixed. This presentation will show the structure of the most energetically favorable configurations along with any systematic trends that are observed as the ratio of C:BN changes. Additionally, we will present the band structure of these combined materials and compare that to the separated cases along with what has been previously published.