Carbon doping effects on the electronic structure of boron nitride

The electronic structure of three series of cubic BN systems are studied by using the linear combination muffin-tin orbitals method with atomic sphere approximation It is shown from the calculations that C atom is a donor in the interstitial and B atom sites, while it is an acceptor in the N atom site. At the different concentration of C atom in the systems, it is possible that the C atom can occupy either the acceptor site or the donor sites at the same time, which is the real reason for one c-BN system simultaneous exhibits n- and p-type conductivities. The density of states of C atoms in different sites are totally different, and the C atom affects more on the density of states of it's neighbor atoms, which reflect the different atomic interaction characteristics between the impurity C atoms and the host atoms.