Comparative Study of Substitutional N and Substitutional P in Diamond

Based on density functional theory calculations, it is found that for substitutional N in diamond the C_3v symmetry structure is more stable, while C_3v and D_2d symmetry patterns for the substitutional P in diamond have comparable energies. Moreover, the substitutional N is a deep donor for diamond, while P is a shallow substitutional n-type dopant. This is attributed to the different doping positions of dopant (the N atom is seriously deviated from the substitutional position, while the P atom nearly locates in the substitutional site), which are determined by the atomic radius.