Quantitative relevance of substitutional impurities to carrier dynamics in diamond

We have quantified substitutional impurity concentrations in synthetic diamond crystals down to sub-parts-per-billion levels. The capture lifetimes of electrons and excitons injected via photoexcitation were compared for several samples with different impurity concentrations. Based on the assessed impurity concentrations, we have determined the capture cross section of electrons for boron impurity, σA=1×10^-144pt0excm², and that of excitons for nitrogen impurity, σDᵉˣ=3×10^-144pt0excm². The general tendency of the mobility values for different carrier species is successfully reproduced by including carrier scattering by impurities and excitons.