Published online by Cambridge University Press: 21 February 2011
Diamond films produced by microwave plasma enhanced chemical vapor deposition (CVD) technique and used to fabricate radiation detectors have been characterized. The polycrystalline diamond films have a measured resistivity of 1012 Ω.cm and a carrier lifetime of about 530 ps. The carrier mobility - lifetime product depends on the density of photogenerated carriers. The carrier mobility decreases from 160 to 13 cm2/V.s for a carrier density increase from 2 × 1011 cm-3 to 3.7 × 1013 cm-3. The detector response to laser pulses (λ= 355, 532 and 1064 nm), X-ray flux (2.5 – 16 keV) and alpha particles (241Am, 5.49 MeV) has been investigated. The response speed of the detector is in the 100 ps range. X-ray photon flux measurements and alpha particle counting capabilities of the CVD diamond detectors are demonstrated.