![]() The study presents the significant recent advance in the technology of room-temperature semiconductor gamma-ray spectrometers. The DC characteristics are correlated with the detector dark noise and the spectral performance. We investigate the performance of n-type MSM spectrometers fabricated with several types of contacts: ohmic anodes and cathode, rectifying anodes and cathode as well as mixed (i.e., ohmic anodes and rectifying cathode). Imaging arrays, which are produced by IMARAD with ohmic contacts are compared with arrays with different types of contacts, fabricated at Technion-Israel Institute of Technology. The intentionally doped n-type CdZnTe crystals are grown by IMARAD Imaging Systems by a modified horizontal Bridgman technique. This study focuses on the characterization of n-type CdZnTe gamma-ray spectrometers, which are designed for pixelated imaging array. The noise measurements are useful for optimizing detector technology. Surface leakage is reducedīy applying surface passivation but is eliminated only by using the three terminal MSM configuration which exhibits simple shot noise instead of the suppressed shot noise observed in the two terminal MSM spectrometers. Mode prevent generation-recombination noise which becomes dominant with injecting contacts (for example MSM detectors withĮvaporated indium and titanium contacts) or when operating the PIN detector in the forward bias mode. Of non-injecting contacts (evaporated gold) for the MSM detectors and the operation of the PIN detector in the reverse bias By reducing the dc value of the dark (leakage) currentīelow 1 nA, shot noise becomes the dominant noise mechanism and the contribution of 1/f noise becomes negligible. The two innovative CdZnTe spectrometerĬonfigurations presented here exhibit very low dark (leakage) current. Terminals as well as heterostructure PIN detectors with thermally evaporated n+ CdS and p+ ZnTe contacts, which are fabricated on high pressure Bridgman CdZnTe (Zn=10%) crystals. Innovative CdZnTe spectrometer configurations are studied: metal-semiconductor-metal (MSM) resistive detectors with three Systematic measurements of dark noise spectra of CdZnTe x- and γ-ray spectrometers, correlated with the dc I-V characteristics and detector technology, are reported.
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