Carrier Recombination And Diffusion In High-Purity Diamond After Electron Irradiation And Annealing

Carrier-transport mechanisms are studied in high-purity diamond irradiated with 6MeV electrons in the dose range of 10(12)-10(16)cm(-2) and annealed at different temperatures up to 1450 degrees C. Lifetimes and diffusion coefficients are extracted using two pump-probe techniques based on free-carrier absorption and transient-grating principles and then correlated with the corresponding defect evolution from spectroscopic measurements. The neutral monovacancy is revealed as the main carrier recombination center in the as-irradiated diamond, providing bipolar carrier lifetimes of a few nanoseconds at the highest irradiation dose. Carrier-capture cross sections are reduced during annealing as vacancies aggregate into divacancies at <= 1000 degrees C and extended vacancy clusters at 1450 degrees C. Published under license by AIP Publishing.