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. 2019 Feb 7;9(1):1620.
doi: 10.1038/s41598-018-38188-w.

Role of selenium addition to CdZnTe matrix for room-temperature radiation detector applications

U N Roy  1 , G S Camarda  2 , Y Cui  2 , R Gul  2 , A Hossain  2 , G Yang  2   3 , J Zazvorka  4 , V Dedic  4 , J Franc  4 , R B James  2   5
Affiliations

Role of selenium addition to CdZnTe matrix for room-temperature radiation detector applications

U N Roy et al. Sci Rep. .

Abstract

Because of its ideal band gap, high density and high electron mobility-lifetime product, cadmium zinc telluride (CdZnTe or CZT) is currently the best room-temperature compound-semiconductor X- and gamma-ray detector material. However, because of its innate poor thermo-physical properties and above unity segregation coefficient for Zn, the wide spread deployment of this material in large-volume CZT detectors is still limited by the high production cost. The underlying reason for the low yield of high-quality material is that CZT suffers from three major detrimental defects: compositional inhomogeneity, high concentrations of dislocation walls/sub-grain boundary networks and high concentrations of Te inclusions/precipitates. To mitigate all these disadvantages, we report for the first time the effects of the addition of selenium to the CZT matrix. The addition of Se was found to be very effective in arresting the formation of sub-grain boundaries and its networks, significantly reducing Zn segregation, improving compositional homogeneity and resulting in much lower concentrations of Te inclusions/precipitates. Growth of the new quaternary crystal Cd1-xZnxTe1-ySey (CZTS) by the Traveling Heater Method (THM) is reported in this paper. We have demonstrated the production of much higher yield according to its compositional homogeneity, with substantially lower sub-grain boundaries and their network, and a lower concentration of Te inclusions/precipitates.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Photograph of the (a) THM grown two-inch diameter Cd0.9Zn0.1Te0.93Se0.07 ingot and (b) a cross-sectional slice of the ingot.
Figure 2
Figure 2
(a) Axial Se and Zn composition (Atomic %) of the as-grown Cd0.9Zn0.1Te0.93Se0.07 ingot (inset shows the sample cut along the length of the ingot), and (b) calculated band-gap along the length of the ingot.
Figure 3
Figure 3
(a) Typical PL spectrum at room temperature and, (b) mapping of peak energy positions (of peak 1) over 4 × 4 cm2 area of the two-inch Cd0.9Zn0.1Te0.93Se0.07 wafer grown by THM.
Figure 4
Figure 4
Typical IR transmission microscopic image showing Te inclusions/precipitates, (a) and (b) different positions.
Figure 5
Figure 5
(a) Size distribution and concentrations of Te inclusions/precipitates and (b) the corresponding 3D distribution for as-grown Cd0.9Zn0.1Te0.93Se0.07 sample by THM.
Figure 6
Figure 6
Resistivity map of two-inch diameter THM grown Cd0.9Zn0.1Te0.93Se0.07 wafer.
Figure 7
Figure 7
Optical photograph of the grain (left) and the corresponding X-ray topographic image of the grain.
See this image and copyright information in PMC

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