Abstract
The effect of deep-level defects is a key issue for the applications of CdZnTe high-flux photon counting devices of X-ray irradiations. However, the major trap energy levels and their quantitive relationship with the device’s performance are not yet clearly understood. In this study, a 16-pixel CdZnTe X-ray photon counting detector with a non-uniform counting performance is investigated. The deep-level defect characteristics of each pixel region are analyzed by the current–voltage curves (I–V), infrared (IR) optical microscope photography, photoluminescence (PL) and thermally stimulated current (TSC) measurements, which indicate that the difference in counting performance is caused by the non-uniformly distributed deep-level defects in the CdZnTe crystals. Based on these results, we conclude that the CdZnTe detectors with a good photon counting performance should have a larger and Cd vacancy-related defect concentration and a lower A-center and Tei concentration. We consider the deep hole trap Tei, with the activation energy of 0.638–0.642 eV, to be the key deep-level trap affecting the photon counting performance. In addition, a theoretical model of the native defect reaction is proposed to understand the underlying relationships of resistivity, deep-level defect characteristics and photon counting performance.
Highlights
There is growing interest in the potential of direct converting semiconductor detectors for the detection of X-rays and γ-rays [1,2,3]
cadmium zinc telluride (CdZnTe) photon counting detectors, which can detect a photon flux in the order of a hundred million mm−2 s−1, are necessary for many applications such as medical and industrial imaging [8,9]. Such high-flux CdZnTe detectors have been reported [10], it is still a challenge to achieve large-scale commercial applications, primarily due to the material defects which can lead to the polarization effect [11,12,13,14,15,16]
The anode of the CdZnTe detector consists of pixels with an area of
Summary
There is growing interest in the potential of direct converting semiconductor detectors for the detection of X-rays and γ-rays [1,2,3]. The high-flux, multi-energy binning X-ray imaging CdZnTe detector technology, based on the pulse mode, has become a research hotspot [5,6,7] CdZnTe photon counting detectors, which can detect a photon flux in the order of a hundred million mm−2 s−1 , are necessary for many applications such as medical and industrial imaging [8,9] Such high-flux CdZnTe detectors have been reported [10], it is still a challenge to achieve large-scale commercial applications, primarily due to the material defects which can lead to the polarization effect [11,12,13,14,15,16]. The key deep-level trap that affects the photon counting performance will be assigned, which may provide ideas for the CdZnTe crystal growth technique for future photon counting applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
