New approaches for making large-volume and uniform CdZnTe and CdMnTe detectors

K. H. Kim; A. E. Bolotnikov; G. S. Camarda; R. Tappero; A. Hossain; Y. Cui; J. Franc; L. Marchini; A. Zappettini; P. Fochuk; G. Yang; R. Gul; R. B. James

doi:10.1109/TNS.2012.2202917

New approaches for making large-volume and uniform CdZnTe and CdMnTe detectors

K. H. Kim, A. E. Bolotnikov, G. S. Camarda, R. Tappero, A. Hossain, Y. Cui, J. Franc, L. Marchini, A. Zappettini, P. Fochuk, G. Yang, R. Gul, R. B. James

Research output: Contribution to journal › Article › peer-review

26 Citations (Scopus)

Abstract

Although CdZnTe (CZT) and CdMnTe (CMT) materials are leading contenders for room-temperature semiconductor detectors, nonetheless, both materials have limitations hindering their full usage in producing economical, uniform, large-volume devices due to their grain/twin boundaries, material purity, secondary-phase Te defects and material segregation. We tried to prevent the generation of twin and subgrain boundaries to achieve large-volume CZT crystals by means of local temperature control between the CZT melt and quartz crucible. Also, we have expanded the understanding of the electrical and structural properties of coherent/incoherent twin boundaries. The high residual impurities in the starting source materials, especially in manganese, were identified as obstacles against obtaining high-performance CMT detectors. We found that purifying manganese telluride (MnTe) via a floating Te melt-zone very effectively removes impurities, leading to better detectors. CMT detectors fabricated with purified material give a 2.1% energy resolution for 662 keV with a ¹³⁷Cs gamma source without any electron-loss corrections. Secondary-phase Te defects deteriorate detector performance due to incomplete charge collection caused by charge trapping. In situ growth interface studies reveal the thermo-migration of Te inclusions to CZT melts and the dependence of Te-inclusion size on the cooling rate. The effective segregation coefficient of Zn in the CdTe host is nearly 1.3, so about 5%-6% of Zn deviation was reported in Bridgman-grown CZT (Zn=10% ingots. Such uncontrolled Zn variations cause a significant variation of the band-gap throughout the ingot and, consequently, affect the nonuniformity of the detectors' responses. Practically, this means that manufacturers cannot cut the ingot parallel to the crystal growth direction. We also demonstrated that the segregation of Zn can be controlled by creating particular thermal environments after growth.

Original language	English
Article number	6236261
Pages (from-to)	1510-1515
Number of pages	6
Journal	IEEE Transactions on Nuclear Science
Volume	59
Issue number	4 PART 3
DOIs	https://doi.org/10.1109/TNS.2012.2202917
Publication status	Published - 2012
Externally published	Yes

Bibliographical note

Funding Information:
Manuscript received February 15, 2012; revised May 09, 2012; accepted May 26, 2012. Date of publication July 10, 2012; date of current version August 14, 2012. This work was supported by the US Department of Energy, Office of Nonproliferation Research and Verification, NA 22. This work has been authored by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH1-886 with the US Department of Energy. K. H. Kim, A. E. Bolotnikov, G. S. Camarda, R. Tappero, Y. Cui, A. Hossain, G. Yang, R. Gul, and R. B. James are with Brookhaven National Laboratory, Upton, NY 11973, USA (e-mail: [email protected]). J. Franc is with Charles University, Prague 121 16, Czech Republic. L. Marchini and A. Zappettini are with IMEM-CNR, Parma 43124, Italy. P. Fochuk is with Chernivisti National University, Chernivtsi 58012, Ukraine. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TNS.2012.2202917

Keywords

II-VI semiconductor materials
X-ray detectors
cadmium compounds
gamma-ray detectors
semiconductor growth
semiconductor radiation detectors

ASJC Scopus subject areas

Nuclear and High Energy Physics
Nuclear Energy and Engineering
Electrical and Electronic Engineering

Access to Document

10.1109/TNS.2012.2202917

Cite this

Kim, K. H., Bolotnikov, A. E., Camarda, G. S., Tappero, R., Hossain, A., Cui, Y., Franc, J., Marchini, L., Zappettini, A., Fochuk, P., Yang, G., Gul, R., & James, R. B. (2012). New approaches for making large-volume and uniform CdZnTe and CdMnTe detectors. IEEE Transactions on Nuclear Science, 59(4 PART 3), 1510-1515. Article 6236261. https://doi.org/10.1109/TNS.2012.2202917

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title = "New approaches for making large-volume and uniform CdZnTe and CdMnTe detectors",

abstract = "Although CdZnTe (CZT) and CdMnTe (CMT) materials are leading contenders for room-temperature semiconductor detectors, nonetheless, both materials have limitations hindering their full usage in producing economical, uniform, large-volume devices due to their grain/twin boundaries, material purity, secondary-phase Te defects and material segregation. We tried to prevent the generation of twin and subgrain boundaries to achieve large-volume CZT crystals by means of local temperature control between the CZT melt and quartz crucible. Also, we have expanded the understanding of the electrical and structural properties of coherent/incoherent twin boundaries. The high residual impurities in the starting source materials, especially in manganese, were identified as obstacles against obtaining high-performance CMT detectors. We found that purifying manganese telluride (MnTe) via a floating Te melt-zone very effectively removes impurities, leading to better detectors. CMT detectors fabricated with purified material give a 2.1% energy resolution for 662 keV with a 137Cs gamma source without any electron-loss corrections. Secondary-phase Te defects deteriorate detector performance due to incomplete charge collection caused by charge trapping. In situ growth interface studies reveal the thermo-migration of Te inclusions to CZT melts and the dependence of Te-inclusion size on the cooling rate. The effective segregation coefficient of Zn in the CdTe host is nearly 1.3, so about 5%-6% of Zn deviation was reported in Bridgman-grown CZT (Zn=10% ingots. Such uncontrolled Zn variations cause a significant variation of the band-gap throughout the ingot and, consequently, affect the nonuniformity of the detectors' responses. Practically, this means that manufacturers cannot cut the ingot parallel to the crystal growth direction. We also demonstrated that the segregation of Zn can be controlled by creating particular thermal environments after growth.",

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author = "Kim, {K. H.} and Bolotnikov, {A. E.} and Camarda, {G. S.} and R. Tappero and A. Hossain and Y. Cui and J. Franc and L. Marchini and A. Zappettini and P. Fochuk and G. Yang and R. Gul and James, {R. B.}",

note = "Funding Information: Manuscript received February 15, 2012; revised May 09, 2012; accepted May 26, 2012. Date of publication July 10, 2012; date of current version August 14, 2012. This work was supported by the US Department of Energy, Office of Nonproliferation Research and Verification, NA 22. This work has been authored by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH1-886 with the US Department of Energy. K. H. Kim, A. E. Bolotnikov, G. S. Camarda, R. Tappero, Y. Cui, A. Hossain, G. Yang, R. Gul, and R. B. James are with Brookhaven National Laboratory, Upton, NY 11973, USA (e-mail: [email protected]). J. Franc is with Charles University, Prague 121 16, Czech Republic. L. Marchini and A. Zappettini are with IMEM-CNR, Parma 43124, Italy. P. Fochuk is with Chernivisti National University, Chernivtsi 58012, Ukraine. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TNS.2012.2202917",

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AU - Kim, K. H.

AU - Bolotnikov, A. E.

AU - Camarda, G. S.

AU - Tappero, R.

AU - Hossain, A.

AU - Cui, Y.

AU - Franc, J.

AU - Marchini, L.

AU - Zappettini, A.

AU - Fochuk, P.

AU - Yang, G.

AU - Gul, R.

AU - James, R. B.

N1 - Funding Information: Manuscript received February 15, 2012; revised May 09, 2012; accepted May 26, 2012. Date of publication July 10, 2012; date of current version August 14, 2012. This work was supported by the US Department of Energy, Office of Nonproliferation Research and Verification, NA 22. This work has been authored by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH1-886 with the US Department of Energy. K. H. Kim, A. E. Bolotnikov, G. S. Camarda, R. Tappero, Y. Cui, A. Hossain, G. Yang, R. Gul, and R. B. James are with Brookhaven National Laboratory, Upton, NY 11973, USA (e-mail: [email protected]). J. Franc is with Charles University, Prague 121 16, Czech Republic. L. Marchini and A. Zappettini are with IMEM-CNR, Parma 43124, Italy. P. Fochuk is with Chernivisti National University, Chernivtsi 58012, Ukraine. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TNS.2012.2202917

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AB - Although CdZnTe (CZT) and CdMnTe (CMT) materials are leading contenders for room-temperature semiconductor detectors, nonetheless, both materials have limitations hindering their full usage in producing economical, uniform, large-volume devices due to their grain/twin boundaries, material purity, secondary-phase Te defects and material segregation. We tried to prevent the generation of twin and subgrain boundaries to achieve large-volume CZT crystals by means of local temperature control between the CZT melt and quartz crucible. Also, we have expanded the understanding of the electrical and structural properties of coherent/incoherent twin boundaries. The high residual impurities in the starting source materials, especially in manganese, were identified as obstacles against obtaining high-performance CMT detectors. We found that purifying manganese telluride (MnTe) via a floating Te melt-zone very effectively removes impurities, leading to better detectors. CMT detectors fabricated with purified material give a 2.1% energy resolution for 662 keV with a 137Cs gamma source without any electron-loss corrections. Secondary-phase Te defects deteriorate detector performance due to incomplete charge collection caused by charge trapping. In situ growth interface studies reveal the thermo-migration of Te inclusions to CZT melts and the dependence of Te-inclusion size on the cooling rate. The effective segregation coefficient of Zn in the CdTe host is nearly 1.3, so about 5%-6% of Zn deviation was reported in Bridgman-grown CZT (Zn=10% ingots. Such uncontrolled Zn variations cause a significant variation of the band-gap throughout the ingot and, consequently, affect the nonuniformity of the detectors' responses. Practically, this means that manufacturers cannot cut the ingot parallel to the crystal growth direction. We also demonstrated that the segregation of Zn can be controlled by creating particular thermal environments after growth.

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New approaches for making large-volume and uniform CdZnTe and CdMnTe detectors

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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