A detector material for a detector is disclosed for use in CT systems, particularly in dual-energy CT systems, including a doped semiconductor. In at least one embodiment, the semiconductor is doped with a donator in a concentration, wherein the concentration of the donator corresponds to at least 50% of the maximum solubility thereof in the semiconductor material, and the donator produces flat imperfections having an excitation energy. The flat imperfections can be ionized and can provide additional freely moveable charge carriers. The freely moveable charge carriers can be captured by the spatially separated deep imperfections and thus reduce the number of the charged deep imperfections. In this way, pure time- and radiation-dependent effects, such as polarization, occur more often. The invention further more relates to the use of the detector material in a CT or dual-energy CT system for generating tomographic images of a test object.