It was noted that the production of n-type doped diamond had proved to be difficult. Thus, P and perhaps S, when in substitutional sites formed a donor. Meanwhile, B - a relatively shallow acceptor – could be passivated by H. Here, ab initio modelling of these dopants and of their complexes with H showed that it was energetically favorable for H to be trapped and to passivate B and P. It was predicted that S, with one H atom, produced shallow donor levels in the band-gap; with a previously unconsidered configuration being the most stable, and producing the shallowest level. It was shown that the S-H pair was stable under conditions of limited H availability. Furthermore, it was shown that it was energetically favorable for both P-H and P-H2 to dissociate to form H2*. The H diffusion in n-type P-doped diamond was inhibited by the formation of immobile H2*. This was in contrast to the case of B-doped diamond, where it was predicted that H2* would dissociate in the presence of substitutional B atoms, to form B-H complexes. It was demonstrated that a recently observed shallow n-type conductivity was unlikely to arisefrom B-D2 complexes, because these complexes would dissociate into B-D plus a distant D interstitial. It was also predicted that they would induce deep levels in the band-gap.

Interaction of Hydrogen with Boron, Phosphorus and Sulfur in Diamond. E.B.Lombardi, A.Mainwood, K.Osuch: Physical Review B, 2004, 70[20], 205201 (12pp)