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Title: Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods

Abstract

Sandia National Laboratories (SNL) is leading an effort to evaluate vertical high pressure Bridgman (VHPB) Cd{sub 1{minus}x}Zn{sub x}Te (CZT) crystals grown in the former Soviet Union (FSU) (Ukraine and Russia), in order to study the parameters limiting the crystal quality and the radiation detector performance. The stoichiometry of the CZT crystals, with 0.04 < x < 0.25, has been determined by methods such as proton-induced x-ray emission (PIXE), x-ray diffraction (XRD), microprobe analysis and laser ablation ICP mass spectroscopy (LA-ICP/MS). Other methods such as triaxial double crystal x-ray diffraction (TADXRD), infrared transmission spectroscopy (IR), atomic force microscopy (AFM), thermoelectric emission spectroscopy (TEES) and laser induced transient charge technique (TCT) were also used to evaluate the material properties. The authors have measured the zinc distribution in a CZT ingot along the axial direction and also its homogeneity. The (Cd+Zn)/Te average ratio measured on the Ukraine crystals was 1.2, compared to the ratio of 0.9--1.06 on the Russian ingots. The IR transmission showed highly decorated grain boundaries with precipitates and hollow bubbles. Microprobe elemental analysis and LA-ICP/MS showed carbon precipitates in the CZT bulk and carbon deposits along grain boundaries. The higher concentration of impurities and the imperfect crystallinity lead to shortermore » electron and hole lifetimes in the range of 0.5--2 and 0.1 {micro}s, respectively, compared to 3--20 and 1--7 {micro}s measured on US spectrometer grade CZT detectors. These results are consistent with the lower resistivity and worse crystalline perfection of these crystals, compared to US-grown CZT. However, recently grown CZT from FSU exhibited better detector performance and good response to alpha particles.« less

Authors:
;  [1];  [2]
  1. Sandia National Labs., Livermore, CA (United States)
  2. Sandia National Labs., Livermore, CA (United States); and others
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
362098
Report Number(s):
CONF-9810154-
Journal ID: JECMA5; ISSN 0361-5235; TRN: IM9933%%482
Resource Type:
Journal Article
Journal Name:
Journal of Electronic Materials
Additional Journal Information:
Journal Volume: 28; Journal Issue: 6; Conference: 1998 U.S. workshop on the physics and chemistry of II-VI materials, Charleston, SC (United States), 20-22 Oct 1998; Other Information: PBD: Jun 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; CRYSTAL STRUCTURE; CADMIUM TELLURIDES; ZINC TELLURIDES; RADIATION DETECTORS; RUSSIAN FEDERATION; UKRAINE; STOICHIOMETRY; MICROSCOPY; SPECTROSCOPY; X-RAY DIFFRACTION

Citation Formats

Hermon, H, Schieber, M, Hebrew Univ., Jerusalem, and James, R B. Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods. United States: N. p., 1999. Web. doi:10.1007/s11664-999-0055-5.
Hermon, H, Schieber, M, Hebrew Univ., Jerusalem, & James, R B. Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods. United States. https://doi.org/10.1007/s11664-999-0055-5
Hermon, H, Schieber, M, Hebrew Univ., Jerusalem, and James, R B. Tue . "Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods". United States. https://doi.org/10.1007/s11664-999-0055-5.
@article{osti_362098,
title = {Analysis of CZT crystals and detectors grown in Russia and the Ukraine by high-pressure Bridgman methods},
author = {Hermon, H and Schieber, M and Hebrew Univ., Jerusalem and James, R B},
abstractNote = {Sandia National Laboratories (SNL) is leading an effort to evaluate vertical high pressure Bridgman (VHPB) Cd{sub 1{minus}x}Zn{sub x}Te (CZT) crystals grown in the former Soviet Union (FSU) (Ukraine and Russia), in order to study the parameters limiting the crystal quality and the radiation detector performance. The stoichiometry of the CZT crystals, with 0.04 < x < 0.25, has been determined by methods such as proton-induced x-ray emission (PIXE), x-ray diffraction (XRD), microprobe analysis and laser ablation ICP mass spectroscopy (LA-ICP/MS). Other methods such as triaxial double crystal x-ray diffraction (TADXRD), infrared transmission spectroscopy (IR), atomic force microscopy (AFM), thermoelectric emission spectroscopy (TEES) and laser induced transient charge technique (TCT) were also used to evaluate the material properties. The authors have measured the zinc distribution in a CZT ingot along the axial direction and also its homogeneity. The (Cd+Zn)/Te average ratio measured on the Ukraine crystals was 1.2, compared to the ratio of 0.9--1.06 on the Russian ingots. The IR transmission showed highly decorated grain boundaries with precipitates and hollow bubbles. Microprobe elemental analysis and LA-ICP/MS showed carbon precipitates in the CZT bulk and carbon deposits along grain boundaries. The higher concentration of impurities and the imperfect crystallinity lead to shorter electron and hole lifetimes in the range of 0.5--2 and 0.1 {micro}s, respectively, compared to 3--20 and 1--7 {micro}s measured on US spectrometer grade CZT detectors. These results are consistent with the lower resistivity and worse crystalline perfection of these crystals, compared to US-grown CZT. However, recently grown CZT from FSU exhibited better detector performance and good response to alpha particles.},
doi = {10.1007/s11664-999-0055-5},
url = {https://www.osti.gov/biblio/362098}, journal = {Journal of Electronic Materials},
number = 6,
volume = 28,
place = {United States},
year = {1999},
month = {6}
}