Influence of electrical contacts on charge collection profiles in CdZnTe studied by IBIC

The lateral and frontal modes of the nuclear microprobe technique ion beam-induced charge collection (IBICC) were used for imaging the electronic properties of CdZnTe room-temperature detectors. The detectors with different contacts (In–In, In–Au, Au–Au) were bombarded with a scanned 4 MeV proton microbeam. By measuring the detector response at bias voltages of up to several hundred volts, charge collection profiles along the thickness of a detector were calculated for different shaping times . Obvious differences between the various contacts were observed in lateral IBICC efficiency profiles that varied in shape, height and smoothness. No hole collection contribution was observed at apllied voltages for all three configurations of the CZT detector. Electron mobility–lifetime products were calculated from measured IBICC efficiency profiles.