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 E_F 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.