Higherature Annealing of CdZnTe Detectors

J. Suh; S. Hwang; H. Yu; Y. Yoon; Aleksey E. Bolotnikov; Ralph B. James; J. Hong; Kihyun Kim

doi:10.1109/TNS.2017.2771378

Higherature Annealing of CdZnTe Detectors

J. Suh, S. Hwang, H. Yu, Y. Yoon, Aleksey E. Bolotnikov, Ralph B. James, J. Hong, Kihyun Kim

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

4 Citations (Scopus)

Abstract

The electrical properties of CdZnTe(CZT) above the melting point of tellurium (Te) inclusions were determined during in situ annealing. The thermal annealing cycles of the CZT detectors were 490 °C, 530 °C, and 570 °C continuously, which were higher than the melting points of elemental Te and Te inclusions and lower than the sublimation temperature of CZT. Unexpectedly, the CZT detectors exhibited very low leakage current at room temperature after the thermal annealing cycles due to the formation of rectifying contacts. The activation energy of high-resistivity CZT was 0.81 eV indicating pinning of Fermi level nearly in the middle of bandgap. At room temperature, CZT detectors with rectifying contacts showed clearly the 59.5-keV gamma-ray peak of Am-241. Observed fluctuations of the leakage current at about 470 °C might have originated from a mixed conductivity of liquid and solid CZT due to the melting of Te inclusions.

Original language	English
Article number	8103821
Pages (from-to)	2966-2969
Number of pages	4
Journal	IEEE Transactions on Nuclear Science
Volume	64
Issue number	12
DOIs	https://doi.org/10.1109/TNS.2017.2771378
Publication status	Published - 2017 Dec

Bibliographical note

Funding Information:
Manuscript received August 25, 2017; revised November 2, 2017; accepted November 4, 2017. Date of publication November 10, 2017; date of current version December 14, 2017. This work was supported in part by the National Research Foundation of Korea through the Ministry of Science, ICT, and Future Planning, South Korea, under Grant NRF-2015M2B2A9032788. J. Suh and J. Hong are with the Department of Applied Physics, Korea University, Sejong 30019, South Korea. S. Hwang and H. Yu are with the Department of Bio-convergence, Korea University, Seoul 02841, South Korea. Y. Yoon is with the Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan. A. E. Bolotnikov is with the Brookhaven National Laboratory, Upton, NY 11971 USA. R. B. James is with the Sivannah River National Laboratory, Aiken, SC 29808 USA. K. Kim is with the Department of Radiology, School of Health and Environmental Science, Korea University, Seoul 02841, South Korea (e-mail: [email protected]). 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.2017.2771378

Publisher Copyright:
© 1963-2012 IEEE.

Keywords

CZT detectors
CdZnTe (CZT)
Schottky barrier
Te inclusions
in situ annealing
pulse-height analyzers

ASJC Scopus subject areas

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

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10.1109/TNS.2017.2771378

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title = "Higherature Annealing of CdZnTe Detectors",

abstract = "The electrical properties of CdZnTe(CZT) above the melting point of tellurium (Te) inclusions were determined during in situ annealing. The thermal annealing cycles of the CZT detectors were 490 °C, 530 °C, and 570 °C continuously, which were higher than the melting points of elemental Te and Te inclusions and lower than the sublimation temperature of CZT. Unexpectedly, the CZT detectors exhibited very low leakage current at room temperature after the thermal annealing cycles due to the formation of rectifying contacts. The activation energy of high-resistivity CZT was 0.81 eV indicating pinning of Fermi level nearly in the middle of bandgap. At room temperature, CZT detectors with rectifying contacts showed clearly the 59.5-keV gamma-ray peak of Am-241. Observed fluctuations of the leakage current at about 470 °C might have originated from a mixed conductivity of liquid and solid CZT due to the melting of Te inclusions.",

keywords = "CZT detectors, CdZnTe (CZT), Schottky barrier, Te inclusions, in situ annealing, pulse-height analyzers",

author = "J. Suh and S. Hwang and H. Yu and Y. Yoon and Bolotnikov, {Aleksey E.} and James, {Ralph B.} and J. Hong and Kihyun Kim",

note = "Funding Information: Manuscript received August 25, 2017; revised November 2, 2017; accepted November 4, 2017. Date of publication November 10, 2017; date of current version December 14, 2017. This work was supported in part by the National Research Foundation of Korea through the Ministry of Science, ICT, and Future Planning, South Korea, under Grant NRF-2015M2B2A9032788. J. Suh and J. Hong are with the Department of Applied Physics, Korea University, Sejong 30019, South Korea. S. Hwang and H. Yu are with the Department of Bio-convergence, Korea University, Seoul 02841, South Korea. Y. Yoon is with the Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan. A. E. Bolotnikov is with the Brookhaven National Laboratory, Upton, NY 11971 USA. R. B. James is with the Sivannah River National Laboratory, Aiken, SC 29808 USA. K. Kim is with the Department of Radiology, School of Health and Environmental Science, Korea University, Seoul 02841, South Korea (e-mail: [email protected]). 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.2017.2771378 Publisher Copyright: {\textcopyright} 1963-2012 IEEE.",

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AU - Hwang, S.

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AU - Yoon, Y.

AU - Bolotnikov, Aleksey E.

AU - James, Ralph B.

AU - Hong, J.

AU - Kim, Kihyun

N1 - Funding Information: Manuscript received August 25, 2017; revised November 2, 2017; accepted November 4, 2017. Date of publication November 10, 2017; date of current version December 14, 2017. This work was supported in part by the National Research Foundation of Korea through the Ministry of Science, ICT, and Future Planning, South Korea, under Grant NRF-2015M2B2A9032788. J. Suh and J. Hong are with the Department of Applied Physics, Korea University, Sejong 30019, South Korea. S. Hwang and H. Yu are with the Department of Bio-convergence, Korea University, Seoul 02841, South Korea. Y. Yoon is with the Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan. A. E. Bolotnikov is with the Brookhaven National Laboratory, Upton, NY 11971 USA. R. B. James is with the Sivannah River National Laboratory, Aiken, SC 29808 USA. K. Kim is with the Department of Radiology, School of Health and Environmental Science, Korea University, Seoul 02841, South Korea (e-mail: [email protected]). 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.2017.2771378 Publisher Copyright: © 1963-2012 IEEE.

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N2 - The electrical properties of CdZnTe(CZT) above the melting point of tellurium (Te) inclusions were determined during in situ annealing. The thermal annealing cycles of the CZT detectors were 490 °C, 530 °C, and 570 °C continuously, which were higher than the melting points of elemental Te and Te inclusions and lower than the sublimation temperature of CZT. Unexpectedly, the CZT detectors exhibited very low leakage current at room temperature after the thermal annealing cycles due to the formation of rectifying contacts. The activation energy of high-resistivity CZT was 0.81 eV indicating pinning of Fermi level nearly in the middle of bandgap. At room temperature, CZT detectors with rectifying contacts showed clearly the 59.5-keV gamma-ray peak of Am-241. Observed fluctuations of the leakage current at about 470 °C might have originated from a mixed conductivity of liquid and solid CZT due to the melting of Te inclusions.

AB - The electrical properties of CdZnTe(CZT) above the melting point of tellurium (Te) inclusions were determined during in situ annealing. The thermal annealing cycles of the CZT detectors were 490 °C, 530 °C, and 570 °C continuously, which were higher than the melting points of elemental Te and Te inclusions and lower than the sublimation temperature of CZT. Unexpectedly, the CZT detectors exhibited very low leakage current at room temperature after the thermal annealing cycles due to the formation of rectifying contacts. The activation energy of high-resistivity CZT was 0.81 eV indicating pinning of Fermi level nearly in the middle of bandgap. At room temperature, CZT detectors with rectifying contacts showed clearly the 59.5-keV gamma-ray peak of Am-241. Observed fluctuations of the leakage current at about 470 °C might have originated from a mixed conductivity of liquid and solid CZT due to the melting of Te inclusions.

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KW - Schottky barrier

KW - Te inclusions

KW - in situ annealing

KW - pulse-height analyzers

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ER -

Higherature Annealing of CdZnTe Detectors

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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