Limitations to n-type doping in diamond: The phosphorus-vacancy complex

In spite of large concentrations of phosphorus being incorporated into. diamond, the material often remains insulating. It is argued that this occurs through the formation of phosphorus-vacancy complexes which are deep accepters and compensate any donor. The complex is analyzed using a first-principles cluster method. In the ionized state, the defect is diamagnetic and cannot give rise to any internal optical transitions although broad band donor-acceptor transitions are expected – and observed – in material codoped with nitrogen.