Advances in CdZnTeSe for Radiation Detector Applications

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.

Learning-based physical models of room-temperature semiconductor detectors with reduced data

“…CZT suffers from major detrimental defects 6 such as compositional inhomogeneity due to non-unity segregation coefficient of Zn 7 , presence of high concentration of secondary phases, Te inclusions and sub-grain boundaries/dislocation walls in high concentration in CZT array. These defects act as trapping centers, hindering localized charge transport and imposes spatial non-uniformity in charge transport properties, thereby adversely affecting the detector performance [8][9][10][11][12][13] .…”

“…CZT suffers from major detrimental defects 6 such as compositional inhomogeneity due to non-unity segregation coefficient of Zn 7 , presence of high concentration of secondary phases, Te inclusions and sub-grain boundaries/dislocation walls in high concentration in CZT array. These defects act as trapping centers, hindering localized charge transport and imposes spatial non-uniformity in charge transport properties, thereby adversely affecting the detector performance [8][9][10][11][12][13] .The efforts to characterize these detectors has been done over last several years. For instance, using thermoelectric emission spectroscopy (TES) and thermally stimulated conductivity (TSC) measurements, the thermal ionization energies of the electron and hole traps were measured 14 .…”

Effects of excess Te on the optical and electrical properties of Cd1−xMgxTe single crystals grown by the modified vertical Bridgman method

“…5,7 In addition, the quaternary compound semiconductor material CdZnTeSe is another alternative material for CdZnTe. 8,9 It is well known that resistivity is one of the important properties of room temperature radiation detectors. The result of high resistivity is low leakage current and little noise, which is very beneficial to the detector.…”

Quaternary Semiconductor Cd1−xZnxTe1−ySey for High-Resolution, Room-Temperature Gamma-Ray Detection

“…Reports that emerged in the latter half of the last decade, pioneered by Brookhaven National Laboratory, established that the addition of chalcogenides such as selenium (Se) in CZT [17] subdues the sub-grain boundary networks to a substantial extent, achieving crystal growth yield exceeding 90%. The stochiometric formula Cd 0.9 Zn 0.1 Te 1−y Se y , commonly referred to as CZTS, with y usually ranging between 0.01 to 0.07, has since been reported by several groups to be a very high-resolution gamma-ray detector [20][21][22][23][24][25]. Although, some of the above-mentioned defects for CZT are also found in CZTS as shown in Figure 1, the recently reported energy resolution of large volume CZTS detectors is approaching the energy resolution goal of 0.5% or less for 662 keV gamma rays as set by the US Department of Energy (DOE).…”