Electronic Band Structure of N and P Dopants in Diamond

The properties of the n-type impurities nitrogen and phosphorus in diamond have been investigated by means of electronic band structure calculations within the framework of the semiempirical extended Huckel tight-binding method. For diamond with the nitrogen and phosphorus substitutional impurities, calculated density of states shows the impurity level deep in the band gap. This property can be derived from the substantial <111> relaxation of the impurity and nearest-neighbor carbon atoms, which is associated with the population of an antibonding orbital between them. The passivated donor property of the P-vacancy complex which lies deep in the gap is also discussed.