Thermally stimulated investigations on diamond based radiation detectors

Recent improvements in the chemical vapour deposition (CVD) technique have enabled the fabrication of detectors for particle as well as photon detecti on applications. However, according to the material quality, it has been sh own that inherent defect concentration may induce significant deterioration of the detection signal. In order to gain better understanding of these ef fects, in this study we have investigated the presence of traps using therm ally stimulated current (TSC) technique for CVD as well as for natural diam ond. In the 100 to 550 K temperature range, TSC revealed six peaks or shoul ders for CVD diamond material grown under different methane concentration. Four trapping levels at 0.3, 0.6, 0.87 and about 1.45 eV could be identifie d. For natural diamond, significant differences in the TSC spectra have bee n observed for two natural diamonds, used as radiation detectors. The corre lation between the presence of trapping levels and the detection properties is discussed. Five energy levels, at 0.3, 0.45, 0.68, 0.78, and 1.37 eV co uld be identified in natural diamonds, whereas four of them were found to b e associated with the poor radiation detection capabilities. Further, the e ffect of annealing treatments was studied for natural diamonds. The results of TSC investigations gave evidence of a trapping level that could be asso ciated with an improvement of the detection properties.