Tunable electronic properties of diamond (100) surface via boron-nitrogen co-termination: A first-principles study

Surface terminations in diamond are indispensable to stabilize the structures and modulate the electronic properties. In this study, we investigate the structural and electronic properties of boron (B) and nitrogen (N) co-terminated diamond (100) surface with various B/N ratios by a global structure prediction method combined with the first-principles calculations. The predicted surface structures (named as BN3, B2N2, and B3N) are dynamically and thermally stable. The diamond surface characteristics change from positive electron affinity (PEA) to negative electron affinity (NEA) as the B/N ratio increases. The BN3 structure has a PEA value of 1.11 eV, and the B2N2 and B3N possess NEA values of −0.01 to −0.97 eV. Furthermore, the B and N related surface states are introduced into the bandgap region of bulk diamond. Consequently, our results will provide the theoretical guidance for designing and fabricating electronic devices based on diamond.