Advances in the crystal growth of semi-insulating CdZnTe for radiation detector applications

Szeles, Csaba; Cameron, Scott E.; Ndap, J.-O.; Chalmers, W.C.

doi:10.1109/tns.2002.803882

Cited by 110 publications

(63 citation statements)

References 15 publications

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“…The detector was fabricated from a 151510 mm 3 single CZT HPB grown crystal manufactured by Yinnel. Au electrodes were patterned onto the crystal faces in a coplanar arrangement on the top face and a single planar cathode on the opposite face ( Fig.…”

Section: Detector and Experimental Setupmentioning

confidence: 99%

“…The formation of precipitates has been attributed to the cooling process and originates from the retrograde solubility in CZT [3], while the creation of Te inclusions has been attributed to morphological instabilities at the growth interface leading to the capture of Te rich droplets from the melt [3]. Typical diameters of Te precipitates range from (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) nm while inclusions have a size in the range 1-50µm [3], making the effects of inclusions more significant. The mechanism(s) leading to reduced detector response due to inclusions are however currently not well understood [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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Synchrotron radiation studies of spectral response features caused by Te inclusions in a large volume coplanar grid CdZnTe detector

Hansson

Owens

Quarati

et al. 2012

Nuclear Instruments and Methods in Physics Research Section A:

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A b s t r a c tWe report preliminary results from a synchrotron radiation study of Te inclusions in a large volume single crystal CdZnTe (CZT) coplanar-grid detector. The experiment was carried out by probing individual inclusions with highly collimated monochromatic X-and -ray beams. It was found that for shallow X-ray interaction depths, the effect of an inclusion on measured energy loss spectra is to introduce a ~10% shift in the peak centroid energy towards lower channel numbers. The total efficiency is however not affected, showing that the net result of inclusions is a reduction in the Charge Collection Efficiency (CCE). For deeper interaction depths, the energy-loss spectra shows the emergence of two distinct peaks, both downshifted in channel number. We note that the observed spectral behavior shows strong similarities with that reported in semiconductors which exhibit polarization effects, suggesting that the underlying mechanism is common.

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Section: Detector and Experimental Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synchrotron radiation studies of spectral response features caused by Te inclusions in a large volume coplanar grid CdZnTe detector

Hansson

Owens

Quarati

et al. 2012

Nuclear Instruments and Methods in Physics Research Section A:

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show abstract

“…Recently, significant progress has been made in growing large single-crystal CdZnTe for detector fabrication. 25,26 However, present day CdZnTe, like other compound semiconductor detector materials, exhibits poor carrier transport properties. In particular, the hole mobility-lifetime product is very small, at ~ 5X10 planar CdZnTe detectors typically give poor spectral response.…”

Section: Cdznte Detectorsmentioning

confidence: 99%

Recent developments in semiconductor gamma-ray detectors

Luke

Amman

Tindall

et al. 2005

J Radioanal Nucl Chem

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The successful development of lithium-drifted Ge detectors in the 1960's marked the beginning of the significant use of semiconductor crystals for direct detection and spectroscopy of gamma rays. In the 1970's, high-purity Ge became available, which enabled the production of complex detectors and multi-detector systems. In the following decades, the technology of semiconductor gamma-ray detectors continued to advance, with significant developments not only in Ge detectors but also in Si detectors and roomtemperature compound-semiconductor detectors. In recent years, our group at Lawrence Berkeley National Laboratory has developed a variety of gamma ray detectors based on these semiconductor materials. Examples include Ge strip detectors, lithium-drifted Si strip detectors, and coplanar-grid CdZnTe detectors. These advances provide new capabilities in the measurement of gamma rays, such as the ability to perform imaging and the realization of highly compact spectroscopy systems.

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“…The performance of CZT is been adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), various types of voids and SP. [1][2][3][4][5][6] However, as the size of useful detectors gradually increased from a few mm 3 to a few cm 3 , the limiting factor in the detector performance seemed to vary from precipitates. [6][7][8] One explanation for formation of Te-rich SP is has been attributed to excess Te in the melt of CZT and CdTe phases.…”

Section: Introductionmentioning

confidence: 99%

Characterization of secondary phases in modified vertical Bridgman growth CZT

et al. 2009

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CdZnTe or "CZT" crystals are highly suitable for use as a room temperature based spectrometer for the detection and characterization of gamma radiation. Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. For example, various structural heterogeneities within the CZT crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary phases (SP) can have a negative impact on the detector performance. In this study, a CZT material was grown by the modified vertical Bridgman growth (MVB) method with zone leveled growth without excess Te in the melt. Visual observations of material from the growth of this material revealed significant voids and SP. Three samples from this material was analyzed using various analytical techniques to evaluate its electrical properties, purity and detector performance as radiation spectrometers and to determine the morphology, dimension and elemental /structural composition of one of the SP in this material. This material was found to have a high resistivity but poor radiation spectrometer performance. It had SP that were rich in polycrystalline aluminum oxide (Al 2 O 3 ), metallic Te and polycrystalline CdZnTe and 15 to 50 µm in diameter. Bulk elemental analyses of sister material from elsewhere in the boule did not contain high levels of Al so there is considerable elemental impurity heterogeneity within the boule from this growth.

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Advances in the crystal growth of semi-insulating CdZnTe for radiation detector applications

Cited by 110 publications

References 15 publications

Synchrotron radiation studies of spectral response features caused by Te inclusions in a large volume coplanar grid CdZnTe detector

Synchrotron radiation studies of spectral response features caused by Te inclusions in a large volume coplanar grid CdZnTe detector

Recent developments in semiconductor gamma-ray detectors

Characterization of secondary phases in modified vertical Bridgman growth CZT

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