Electronic structure calculations of oxygen-doped diamond using DFT technique

Abstract

In this study, equilibrium geometry and band structure of oxygen-doped diamond have been investigated based on density function theory (DFT) using VASP code. These calculations have shown that the highest occupied molecular orbital is localized at the oxygen atom. Moreover, C4O bond lengths are equivalent to those of CC bonds leading to no lattice distortions. Doping of oxygen into diamond seems to be thermodynamically favorable due to negative formation energy. Band structure calculations lead to the semiconducting behavior of oxygen-doped diamonds due to the creation of defects states inside the band gap extending to conduction band minimum. The spin projected density of states calculations illustrates significant contributions of O 2p states at the Fermi level without the appearance of appreciable magnetic moments on oxygen or on carbon atoms (for all C1–C4) leading to its non-magnetic semi-conducting behavior with zero density of carriers at the Fermi level for both spin projections; O↓↑(EF)=0. Present DFT results verify our experimental findings that addition of oxygen into diamond lattice increases its conductivity so that oxygen-doped diamond films behave like a good semiconductor.