The electronic properties and band-gap discontinuities at the cubic boron nitride/diamond hetero-interface

Abstract

Clarifying the electronic states and structures of the c-BN/diamond interface is of extreme importance for bundling these two different wide-band gap materials in order to synthesize hybrid structures with new functional properties. In this work, the structural optimization and property determinations were carried out on (100) and (111) c-BN/diamond hetero-interface by using first principles total energy calculations. A 12-layers c-BN above the diamond was found to be energetically reasonable for the calculations of the properties of the hetero-interface. Based on the calculation of the chemical potentials for the c-BN/diamond interface, the hetero-interface with the C-B configuration is the most energetically favorable structure under the (111) and (100) surfaces of diamond, respectively. The calculations of band structure and density of states for C-N bond configuration indicate that the main contribution to the density of the interface states near the EF is from the N 2s 2p, B 2p and C 2p orbitals while that for C-B bond configuration is mainly from the B 2p, N 2p and C 2p orbitals. The electron density difference, binding energy and band offset were also calculated, demonstrating that the C-B bond was found to be remarkably stronger than other adjacent bonds. Furthermore, a band offset of 0.587 eV for the (111) c-BN/diamond hetero-interface with the C-N bond configuration has been obtained, which is in good agreement with the previous experimental result (0.8 eV), suggestting that the C-N bond may exist in synthesized c-BN/diamond epitaxy using different growth methods. This should allow the design of a hybrid structure of c-BN/diamond thereby opening a new pathway towards high temperature electronics, UV photonics and (bio-) sensor applications.