Influence of electrical defects on diamond detection properties

The remarkable properties of diamond, together with its radiation hardness, make it an attractive material for specific applications in X-rays and cha rged particle detection. Because electrically active defects are known to i nfluence the detection properties, a thorough study of these defects is of great interest in order to improve the detector characteristics. In this work, the response of diamond devices to X-rays and alpha particles is investigated and the results are correlated with the presence of traps analysed using thermally stimulated current (TSC) methods. The results of T SC analysis on natural diamond have enabled the determination of the energy of three levels activated near room temperature at 0.7, 0.71 and 0.95 eV a nd of a main principal level on CVD diamond at 1.2 eV activated near 550 K. The comparative study of TSC measurements and time dependent X-ray sensiti vity are investigated on natural diamonds. The results confirm the improvem ent of the detection properties after having filled deep trap levels, and s how a detrimental effect of the trapping levels emptied at room temperature on the turnoff time of diamond. Further, the temperature dependence of the detector response under alpha particles was also investigated. Clearly, a temperature increase above a level activated at 375 K leads to the improvem ent of the detection properties. (C) 2000 Elsevier Science S.A. All rights reserved.