Temperature-gradient annealing of CdZnTe under Te overpressure

K. H. Kim; J. Suh; A. E. Bolotnikov; P. M. Fochuk; O. V. Kopach; G. S. Camarda; Y. Cui; A. Hossain; G. Yang; J. Hong; R. B. James

doi:10.1016/j.jcrysgro.2012.03.058

Temperature-gradient annealing of CdZnTe under Te overpressure

K. H. Kim, J. Suh, A. E. Bolotnikov, P. M. Fochuk, O. V. Kopach, G. S. Camarda, Y. Cui, A. Hossain, G. Yang, J. Hong, R. B. James

School of Health and Environmental Science

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

28 Citations (Scopus)

Abstract

The performance of CdZnTe (CZT) detectors is limited not only by conventional carrier-trapping to point defects but also by trapping at macroscopic Te secondary-phase defects, such as Te inclusions and Te precipitates. The aim of this research is to remove these secondary-phase defects via thermomigration, and to obtain high resistivity of the material by creating Te antisites through annealing in a high Te overpressure. We annealed Te-rich CZT samples in the temperature range between 500 and 700 °C under Te overpressure with a temperature gradient of 50-60 °C/cm. We investigated the effects of annealing under these conditions by IR transmission microscopy, current-voltage measurements, photoluminescence, and white-beam X-ray diffraction topography (WBXDT) measurements comparing the findings with those from isothermally annealed CZT samples under Cd overpressure. We proved experimentally that Te inclusions present in Te-rich CZT melts contain void fractions. We attributed the complex defect of Te antisites with Cd vacancies in our annealing experiment as the deep level defect that pins the Fermi near the middle of the bandgap, rather than the Te antisite.

Original language	English
Pages (from-to)	62-66
Number of pages	5
Journal	Journal of Crystal Growth
Volume	354
Issue number	1
DOIs	https://doi.org/10.1016/j.jcrysgro.2012.03.058
Publication status	Published - 2012 Sept 1

Bibliographical note

Funding Information:
This work was supported by the U.S. Department of Energy , Office of Nonproliferation Research and Development, NA-22 and the Defense Threat Reduction Agency .

Keywords

A1. Defects
A1. X-ray topography
A2. Bridgman technique
B1. Cadmium compounds
B2. Semiconducting II-VI materials

ASJC Scopus subject areas

Condensed Matter Physics
Inorganic Chemistry
Materials Chemistry

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10.1016/j.jcrysgro.2012.03.058

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title = "Temperature-gradient annealing of CdZnTe under Te overpressure",

abstract = "The performance of CdZnTe (CZT) detectors is limited not only by conventional carrier-trapping to point defects but also by trapping at macroscopic Te secondary-phase defects, such as Te inclusions and Te precipitates. The aim of this research is to remove these secondary-phase defects via thermomigration, and to obtain high resistivity of the material by creating Te antisites through annealing in a high Te overpressure. We annealed Te-rich CZT samples in the temperature range between 500 and 700 °C under Te overpressure with a temperature gradient of 50-60 °C/cm. We investigated the effects of annealing under these conditions by IR transmission microscopy, current-voltage measurements, photoluminescence, and white-beam X-ray diffraction topography (WBXDT) measurements comparing the findings with those from isothermally annealed CZT samples under Cd overpressure. We proved experimentally that Te inclusions present in Te-rich CZT melts contain void fractions. We attributed the complex defect of Te antisites with Cd vacancies in our annealing experiment as the deep level defect that pins the Fermi near the middle of the bandgap, rather than the Te antisite.",

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author = "Kim, {K. H.} and J. Suh and Bolotnikov, {A. E.} and Fochuk, {P. M.} and Kopach, {O. V.} and Camarda, {G. S.} and Y. Cui and A. Hossain and G. Yang and J. Hong and James, {R. B.}",

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doi = "10.1016/j.jcrysgro.2012.03.058",

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T1 - Temperature-gradient annealing of CdZnTe under Te overpressure

AU - Kim, K. H.

AU - Suh, J.

AU - Bolotnikov, A. E.

AU - Fochuk, P. M.

AU - Kopach, O. V.

AU - Camarda, G. S.

AU - Cui, Y.

AU - Hossain, A.

AU - Yang, G.

AU - Hong, J.

AU - James, R. B.

N1 - Funding Information: This work was supported by the U.S. Department of Energy , Office of Nonproliferation Research and Development, NA-22 and the Defense Threat Reduction Agency .

PY - 2012/9/1

Y1 - 2012/9/1

N2 - The performance of CdZnTe (CZT) detectors is limited not only by conventional carrier-trapping to point defects but also by trapping at macroscopic Te secondary-phase defects, such as Te inclusions and Te precipitates. The aim of this research is to remove these secondary-phase defects via thermomigration, and to obtain high resistivity of the material by creating Te antisites through annealing in a high Te overpressure. We annealed Te-rich CZT samples in the temperature range between 500 and 700 °C under Te overpressure with a temperature gradient of 50-60 °C/cm. We investigated the effects of annealing under these conditions by IR transmission microscopy, current-voltage measurements, photoluminescence, and white-beam X-ray diffraction topography (WBXDT) measurements comparing the findings with those from isothermally annealed CZT samples under Cd overpressure. We proved experimentally that Te inclusions present in Te-rich CZT melts contain void fractions. We attributed the complex defect of Te antisites with Cd vacancies in our annealing experiment as the deep level defect that pins the Fermi near the middle of the bandgap, rather than the Te antisite.

AB - The performance of CdZnTe (CZT) detectors is limited not only by conventional carrier-trapping to point defects but also by trapping at macroscopic Te secondary-phase defects, such as Te inclusions and Te precipitates. The aim of this research is to remove these secondary-phase defects via thermomigration, and to obtain high resistivity of the material by creating Te antisites through annealing in a high Te overpressure. We annealed Te-rich CZT samples in the temperature range between 500 and 700 °C under Te overpressure with a temperature gradient of 50-60 °C/cm. We investigated the effects of annealing under these conditions by IR transmission microscopy, current-voltage measurements, photoluminescence, and white-beam X-ray diffraction topography (WBXDT) measurements comparing the findings with those from isothermally annealed CZT samples under Cd overpressure. We proved experimentally that Te inclusions present in Te-rich CZT melts contain void fractions. We attributed the complex defect of Te antisites with Cd vacancies in our annealing experiment as the deep level defect that pins the Fermi near the middle of the bandgap, rather than the Te antisite.

KW - A1. Defects

KW - A1. X-ray topography

KW - A2. Bridgman technique

KW - B1. Cadmium compounds

KW - B2. Semiconducting II-VI materials

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Temperature-gradient annealing of CdZnTe under Te overpressure

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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