Spectroscopic response of CZT detectors obtained by the boron encapsulated vertical Bridgman method

A great effort is being presently devoted in growing and studying CdTe and CdZnTe detectors which can be used in a large variety of applications, such as the basic, medical, industrial, and space research. The purpose of this work is to present the spectral response at different energies of some CZT crystals grown with the boron oxide encapsulated vertical Bridgman method by IMEM-CNR. The most important feature of this technique is that the crystal, during the growth, is fully encapsulated by a thin layer of liquid boron oxide, so that the crystal-crucible contact is prevented. Using this material, several detectors were realized of about 4x4xl mm3 in size and with electrical gold contacts on both the surfaces obtained by the electroless technique. The behavior of these detectors was studied as a function of the bias voltage, shaping time and energy of the interacting photons. The charge transport properties (µtt products) were measured with radioactive sources. We present the main results of the spectroscopic characterization of some samples.