Advances in CdZnTeSe for Radiation Detector Applications
1
Savannah River National Laboratory, Aiken, SC 29808, USA
2
Brookhaven National Laboratory, Upton, NY 11973, USA
*
Author to whom correspondence should be addressed.
Radiation 2021, 1(2), 123-130; https://doi.org/10.3390/radiation1020011
Submission received: 16 March 2021
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Revised: 5 April 2021
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Accepted: 8 April 2021
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Published: 25 April 2021
Simple Summary
Cadmium-zinc-telluride is the most important semiconductor material today for room temperature gamma-ray detector applications. The radiation detectors are widely used for medical imaging, homeland security, and X- and gamma-ray astronomy. However, the material has longstanding technological problems. Despite significant improvements over the past 3 decades, the technology still suffers from major detrimental defects such as a high concentration of tellurium inclusions and sub-grain boundary network/dislocation walls, which adversely impact the yield of high-quality detectors fabricated from the crystals. To address these challenges, selenium was added to the cadmium zinc telluride matrix. The Se addition was found to have a profound effect to reduce the deleterious defects in the crystals. The resulting cadmium-zinc-telluride-selenide material was found to be free from a sub-grain boundary network with reduced tellurium inclusions. Thus, cadmium zinc telluride selenide material is a promising approach to increase the yield of high-quality radiation detectors as compared to cadmium zinc telluride. This paper reports a path to the advancement of the quaternary material to achieve the best detector performance. This advance may resolve the longstanding issues associated with cadmium zinc telluride-based X- and gamma-ray detectors.
Abstract
Detection of X- and gamma-rays is essential to a wide range of applications from medical imaging to high energy physics, astronomy, and homeland security. Cadmium zinc telluride (CZT) is the most widely used material for room-temperature detector applications and has been fulfilling the requirements for growing detection demands over the last three decades. However, CZT still suffers from the presence of a high density of performance-limiting defects, such as sub-grain boundary networks and Te inclusions. Cadmium zinc telluride selenide (CZTS) is an emerging material with compelling properties that mitigate some of the long-standing issues seen in CZT. This new quaternary is free from sub-grain boundary networks and possesses very few Te inclusions. In addition, the material offers a high degree of compositional homogeneity. The advancement of CZTS has accelerated through investigations of the material properties and virtual Frisch-grid (VFG) detector performance. The excellent material quality with highly reduced performance-limiting defects elevates the importance of CZTS as a potential replacement to CZT at a substantially lower cost.
Keywords:
radiation detector; CdZnTeSe; X-ray topography; defects; Te inclusions
