Correlations Between Crystal Defects and Performance of CdZnTe Detectors

Compositional homogeneity and X-ray topographic analyses of CdTe Se1− grown by the vertical Bridgman technique

“…We note that the overall concentration of sub-grain boundaries and their networks in our CTS samples for all concentrations of Se studied are much less than CZT/CdTe [18,23]. As discussed earlier, the sub-grain boundaries and their networks severely degrade the charge transport properties and hence, the device's performance [18], and they are also responsible for much of the spatial non-uniformity of the charge collection efficiency for large area/volume detectors [24,25].…”

“…The appearance of few subgrain boundaries in the diffracted image also confirms the effectiveness of solid-solution hardening by Se compared to Zn in the CdTe matrix. High concentrations of sub-grain boundaries and their networks are very commonly observed in CZT and CdTe ingots, irrespective of growth method [18,23]. Figures 5a and 5b are photographs of a polished wafer cut perpendicular to the ingot axis of a CTS ingot grown with 7% Se concentration, and the corresponding X-ray diffraction topographic image.…”

“…Recently, our Traveling Heater method (THM)-grown CTS with 10% Se also showed the presence of very few sub-grain boundaries and the absence of a sub-grain boundary network [17]. It is well known that the presence of sub-grain boundaries and their networks have a severe detrimental effect on carrier trapping, and consequently, on the performance of charge-collection devices [18]; hence, the fewer sub-grain boundaries and the absence of their networks in CTS is expected to assure better charge-transport characteristics and homogeneity. The Te inclusions/precipitations in the CZT matrix play a significant cumulative role in degrading the performance of devices [19,20], which becomes more pronounced for larger device's thicknesses.…”

Development of CdZnTe radiation detectors

“…Its X-ray response map is shown in Figure 7(a) [9]. The spectral response (Figure 7(b)) has two photopeaks, indicating that defects along the grain boundary trap a large amount of charge shifting the photo-peak signals [9].…”

CdTexSe1-x: a potential candidate for room-temperature radiation detector applications

“…Another of its major advantages is the effective solid solution hardening due to Se 1,5 in arresting the formation of sub-grain boundaries and their networks in the CdTe matrix compared to Zn, which is a significant advantage for CTS over CZT and results in obtaining CTS ingots free from sub-grain boundary networks 1,5 . The presence of a high density of sub-grain boundary networks in CZT is responsible for degrading the detector's response, and also accounts for non-uniformity in spatial charge-transport 6 . The high density of secondary phases (Te inclusions/precipitations) is a long-standing problem of CZT, and severely degrades its charge-transport properties, and hence, the detector's response 7 .…”