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Title: Control of electric field in CdZnTe radiation detectors by above-bandgap light

We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states.
Authors:
; ; ; ;  [1] ;  [2] ;  [3]
  1. Institute of Physics of Charles University, Prague (Czech Republic)
  2. Crytur Ltd., Turnov (Czech Republic)
  3. Department of Physics, University of Surrey, Guildford (United Kingdom)
Publication Date:
OSTI Identifier:
22402954
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CADMIUM COMPOUNDS; CATHODES; DEPOLARIZATION; ELECTRIC CURRENTS; ELECTRIC FIELDS; ELECTRONIC STRUCTURE; ELECTRONS; ENERGY GAP; EXCITATION; HOLES; ILLUMINANCE; POLARIZATION; RADIATION DETECTORS; SPACE CHARGE; TRAPPING; VISIBLE RADIATION; X RADIATION; ZINC TELLURIDES