Radiation resistance of wide-gap materials as exemplified by SiC nuclear radiation detectors

摘要

In wide-gap materials used in nuclear detectors, the polarization effect is typically observed when the concentration of radiation-induced defects is high. An emf arising in the detector is associated with long-term trapping of charge carries by deep radiation-induced levels (centers). The polarization kinetics and the polarization field strength are determined experimentally. The trapping efficiency can be controlled by varying the temperature, and a tradeoff can be reached at an "optimal" temperature between the generation current and the position of the deepest level, which has a negligible effect on charge losses via trapping. It is found that the ratio between the depth of this level and the bandgap is about 1/3 irrespective of the material but the optimal temperature is material-specific.