Te Inclusions in CZT Detectors: New Method for Correcting Their Adverse Effects

Bolotnikov, A. E.; Babalola, Stephen; Camarda, G. S.; Cui, Yonggang; Egarievwe, Stephen U.; Hawrami, R.; Hossain, Anwar; Yang, Ge; James, R. B.

doi:10.1109/tns.2010.2042617

Cited by 52 publications

(39 citation statements)

References 16 publications

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“…Figure 5a shows a typical 3D volumetric distribution of Te inclusions/precipitations over the volume of 1x1.5x3 mm 3 for CZT grown using our THM method. The total concentration of the Te inclusions/precipitations over the scanned volume was estimated to be 1.3x10 5 cm -3 and is comparable to the recently reported value for commercially available CZT samples [11]. The size distribution of the Te inclusions/precipitations over the same volume is shown in Fig.…”

Section: Resultssupporting

confidence: 86%

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Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement

et al. 2011

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In this present work we report the growth of Cd 0.9 Zn 0.1 Te doped with In by a modified THM technique. It has been demonstrated that by controlling the microscopically flat growth interface, the size distribution and concentration can be drastically reduced in the as-grown ingots. This results in as-grown detector-grade CZT by the THM technique. The three-dimensional size distribution and concentrations of Te inclusions/precipitations were studied. The size distributions of the Te precipitations/inclusions were observed to be below the 10-µm range with the total concentration less than 10 5 cm -3 . The relatively low value of Te inclusions/precipitations results in excellent charge transport properties of our as-grown samples. The (µτ) e values for different as-grown samples varied between 6-20 x10 -3 cm 2 /V. The as-grown samples also showed fairly good detector response with resolution of ~1.5%, 2.7% and about 3.8% at 662 keV for quasi-hemispherical geometry for detector volumes of 0.18 cm 3 , 1 cm 3 and 4.2 cm 3 , respectively.

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Section: Resultssupporting

confidence: 86%

“…histogram extends below 10 µm, and was consistent at different positions of the wafers and also for different ingots, while the distribution was recently reported to be extend from 15-25 µm for many commercially available CZT samples [11]. It is also evident that most of the concentrations are around or below 3 µm as shown in Fig.…”

Section: Resultssupporting

confidence: 81%

Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement

et al. 2011

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“…The wafers possessed a similar resistivity of >3x10 10 Ohm-cm, and an electron μτ-product of >7x10 -3 cm 2 /V, as measured by the vendor. Later, our more accurate measurements of the μτ-products yielded a typical value of >2x10 -2 cm 2 /V.…”

Section: Methodsmentioning

confidence: 77%

“…Later, our more accurate measurements of the μτ-products yielded a typical value of >2x10 -2 cm 2 /V. First, we characterized the wafers using IR transmission microscopy to measure the concentrations and size distributions of Te inclusions by taking "in depth" images of 1.1x1.5 mm 2 areas at different locations [10]. The concentration of Te inclusions was the same within a factor of ~2 over the wafers' areas, except for the regions containing decorated grain boundaries.…”

Section: Methodsmentioning

confidence: 99%

Array of virtual Frisch-grid CZT detectors with common cathode readout and pulse-height correction

et al. 2010

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We present our new results from testing 15-mm-long virtual Frisch-grid CdZnTe detectors with a common-cathode readout for correcting pulse-height distortions. The array employs parallelepiped-shaped CdZnTe (CZT) detectors of a large geometrical aspect ratio, with two planar contacts on the top and bottom surfaces (anode and cathode) and an additional shielding electrode on the crystal's sides to create the virtual Frisch-grid effect. We optimized the geometry of the device and improved its spectral response. We found that reducing to 5 mm the length of the shielding electrode placed next to the anode had no adverse effects on the device's performance. At the same time, this allowed corrections for electron loss by reading the cathode signals to obtain depth information.

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“…However, the material's inhomogeneity in bulk grown detectorgrade CZT crystals, especially due to the structure imperfections, still creates a 'bottle-neck' in state of the art wafer assessment and screening, which has consequently reduced the availability and increased the cost of CZT materials. These commercial restrictions have prevented the wide-spread adoption of CZT for various general applications, such as medical imaging, industrial monitoring and national security [7,8].…”

Section: Introductionmentioning

confidence: 99%