A method was proposed for selectively characterizing the traps which were involved in the pumping of diamond films. The pumping process strongly reduced the concentration of active carrier trapping centers; thus leading to an enhancement of the electronic properties. It was obtained by irradiating the films with ionizing radiation. Because the improved transport properties led to an increased efficiency when the films were used as radiation detectors, information on the process could be obtained by analyzing the response of diamond-based particle detectors. A high-quality diamond film was therefore grown by microwave chemical vapor deposition, and a particle detector was built. Its response to 5.5MeV 241Am α-particles was measured after successive annealing steps at 180 to 228C. Before determining each annealing curve at a given temperature, the detector was driven to the pumped state by β-particle irradiation. The efficiency versus annealing time curves revealed thermally-induced de-trapping. This confirmed that the pumping mechanism involved the filling and passivation of defects. Analysis of the decay time of the detector efficiency, as a function of temperature, indicated that the activation energy of these defects was 1.62eV.

Thermal Detrapping Analysis of Pumping-Related Defects in Diamond. M.Marinelli, E.Milani, M.E.Morgada, G.Pucella, G.Rodriguez, A.Tucciarone, G.Verona-Rinati, M.Angelone, M.Pillon: Applied Physics Letters, 2003, 83[18], 3707-9