First principles investigation on the boron-oxygen complexes in diamond

The co-doping mechanism of boron and oxygen substitutional complexes in diamond are investigated since the B-O co-doping seems to be a solution for preparing n-type diamond in some experiments. We use first-principles calculations to predict the geometry of a range of B-O complexes in diamond. Three possibly stable configurations are confirmed through the formation energy and binding energy. We also find that B-rich complexes are more stable when O sits in the centre position, whereas O tends to be closer to another O in the case of O-rich complexes. Electrically, the former shows a shallow acceptor property while the latter is a neutral impurity by analysing the transition levels, band structures and partial density of states. Our calculation suggests that the B-O scheme may not be a feasible way for effective n-type diamond, but it might be a good method to prepare high-quality p-type diamonds.