Electrically active defects in detector-grade CdTe:Cl and CdZnTe materials grown by THM and HPBM

High resistive CdTe is one of the key materials of room-temperature radiation detectors. For these materials, deep levels play an important role on the electrical as well as transport properties and, therefore, drastically affect the performance of the nuclear detectors. In this work, we report the electrical properties of several materials mainly for two types of investigated crystals: THM doped by chlorine with and without additional dopants; HPBM (high pressure Bridgman method). A variety of high sensitivity characterization and analytical methods were used, including TSC (thermally stimulated current), Van der Pauw resistivity analysis as well as nuclear detection. The similarities as well as differences of these two categories of materials with and without controlled chemical impurities will be described with a tentative assignment of each considered chemical to a deep defect level.