Luminescence induced by N-O ion implantation into diamond

The incorporation of shallow n-type dopants in diamond is one of the major challenges for its electronic applications. n-Type behaviour in diamond has been observed for substitutional phosphorus and nitrogen, with activation energies of approximately 0.62 and 1.7 eV, respectively. Both nitrogen and phosphorus are deep lying substitutional impurity states in diamond. It has been theoretically found that the substitution of the N-O molecule into the diamond lattice forms a stable defect in the band gap and, in the negatively charged state induces a shallow defect below the conduction band edge which may lead to n-type conductivity. In this study, low-temperature photoluminescence measurements using different excitation wavelengths were used to investigate the nature and behaviour of the defects induced by the implantation of N-O ions into type IIa Chemical Vapor Deposition (CVD) diamond samples. Luminescence peaks were observed at 293.3, 297.3, 305.9, 309.8, 314.4 and 556.7 nm on the sample which was implanted by N-O ions and annealed at 600 degrees C. The origin of these peaks is discussed and the mechanism of electronic transitions leading to emission of photoluminescence from these samples is proposed.