An investigation of the electronic structure of charged vacancies and X(C),
X=(As, Sb, P) substitutional centers in diamond has been carried out by
means of ab initio density functional theory. The revised
Heyd-Scuseria-Ernzerhof screened hybrid functional (HSE06) was utilized for the
total energy calculation. The equilibrium geometry, defect charge transition
levels and energetics of the vacancies and substitutional centers were
determined. It is found that substitutional As and Sb introduce a donor level
into the band gap about 0.5 eV with respect to the conduction band minimum
(CBM), therefore, these elements may be a good choice for achieving n-type
diamond. From a technological point of view, however, fabrication of As and Sb
doped diamond would be challenging due to its high, positive formation
energy.