Electronic Structure and N-Type Doping in Diamond from First Principles

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.