The charge transport properties and radiation detector performance of semi-insulating CdTe single crystal grown by the conventional vertical Bridgman technique in this paper. The measured room-temperature electrical resistivity of the crystals is below the theoretical maximum allowed by the band gap of CdTe indicating incomplete electrical compensation of the material. The crystals show excellent spectroscopic performance in the 15 keV - 662 keV energy range, with reduced low-energy tailing in the photopeaks. The energy resolution of the best detector was 2.7 keV full width half maximum (FWHM) at 59.5 keV, 4.5 keV FWHM at 122 keV, and 20.1 keV FWHM at 662 keV. This improved performance is attributed to the improved hole transport over the typical HPB CdZnTe. The measured mobility-lifetime product of holes, (mu) (tau) h approximately equals 2.3 X 10-4 cm2/V, is significantly higher than that typical for HPB CdZnTe crystals. The measured electron (mu) (tau) e approximately equals 1.6 X 10-3 cm2/V of these CdTe crystals suggest somewhat poorer electron transport than in a spectroscopic grade HPB material.
Cadmium zinc telluride (CZT) gamma-ray detectors show great potential in medical and nuclear material imaging applications. These imagers rely on pixellated arrays of CZT for their operation. Systematic and random material variation among the pixels can introduce noise into the system and makes data analysis more complicated. Photo induced transient current spectroscopy (PICTS), and low temperature photoluminescence have been employed to analyze 4 by 4 pixellated arrays and to determine material variation among the pixels. Particular pixels that have proven to perform well or poorly have been studied in detail to try and identify the origin of this performance variation. This paper reports preliminary results and comments on future analysis.
We have applied several techniques, including photoluminescence, proton-induced x-ray emission, photocurrent, and alpha particle response mapping, for mapping micron- and millimeter-scale variations in cadmium zinc telluride. We have correlated the degree of inhomogeneity determined by these techniques with performance of gamma-ray spectrometers fabricated from the material.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.