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Proceedings Paper

Reduced leakage currents of CdZnTe radiation detectors with HgTe/HgCdTe superlattice contacts
Author(s): Y. Chang; C. H. Grein; C. R. Becker; J. Huang; S. Ghosh; F. Aqariden; S. Sivananthan
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Paper Abstract

Room-temperature-operating CdZnTe radiation detectors have high energy resolution, linear energy response and are capable of operating in normal counting and spectroscopic modes, hence are highly desirable for medical diagnosis, nondestructive industrial evaluations, homeland security, counterterrorism inspections and nuclear proliferation detection to ensure national and international nuclear safety. HgTe/HgCdTe superlattices can be designed to selectively transport one carrier species while hindering transport of the other. Specifically, one designs a large carrier effective mass for undesired carriers in the electric field direction, which results in low carrier velocities, and yet a density of states for undesired carrier that is lower than that of a comparable bulk semiconductor, which results in low carrier concentrations, hence a low current density under an electric field. The opposite carrier species can be designed to have a large velocity and high density of states, hence producing a large current density. By employing HgTe/HgCdTe superlattices as contact layers intermediate between CdZnTe absorbers and metal contacts, leakage currents under high electric fields are reduced and improved x-ray and γ-ray detector performance is anticipated. Pixilated CdZnTe radiation detectors arrays were fabricated and characterized to evaluate the effectiveness of HgTe/HgCdTe superlattices in reducing leakage currents. Current-voltage characteristics show that HgTe/HgCdTe superlattice contact layers consistently result in significantly reduced leakage currents relative to detectors with only metal contacts.

Paper Details

Date Published: 24 October 2012
PDF: 10 pages
Proc. SPIE 8507, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XIV, 850715 (24 October 2012); doi: 10.1117/12.949354
Show Author Affiliations
Y. Chang, Univ. of Illinois at Chicago (United States)
C. H. Grein, Univ. of Illinois at Chicago (United States)
C. R. Becker, Univ. of Illinois at Chicago (United States)
J. Huang, Univ. of Illinois at Chicago (United States)
S. Ghosh, Univ. of Illinois at Chicago (United States)
F. Aqariden, Sivananthan Labs., Inc. (United States)
S. Sivananthan, Univ. of Illinois at Chicago (United States)

Published in SPIE Proceedings Vol. 8507:
Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XIV
Ralph B. James; Arnold Burger; Larry A. Franks; Michael Fiederle, Editor(s)

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