Study of electric field distribution and low frequency noise of CdZnTe radiation detectors

Polarization phenomena in a metal-semiconductor-metal (M-S-M) structure of metallic Schottky contacts deposited on CdZnTe radiation detectors were studied. We evaluate the distribution of the electric field along the biased M-S-M structure by Pockels measurements. The results show that almost all th...

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Bibliographic Details
Published in:Journal of instrumentation 2013-06, Vol.8 (6), p.1-5
Main Authors: Sik, O, Grmela, L, Elhadidy, H, Dedic, V, Sikula, J, Grmela, P, Franc, J, Skarvada, P, Holcman, V
Format: Article
Language:English
Subjects:
Cadmium zinc tellurides
Construction
Detectors
Electric contacts
Electric fields
Noise
Polarization
Radiation detectors
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Summary:Polarization phenomena in a metal-semiconductor-metal (M-S-M) structure of metallic Schottky contacts deposited on CdZnTe radiation detectors were studied. We evaluate the distribution of the electric field along the biased M-S-M structure by Pockels measurements. The results show that almost all the electric field is developed across the depletion layer of the reverse-biased contact. The noise measurements of the CdZnTe detectors studied show that the dominant noise is 1/f super(m) noise. The 1/f super(m) noise, with the parameter m close to one, is present at frequencies below 100 Hz and its bandwidth decreases in the course of the polarization process. At higher frequencies, we observed an increase of the m parameter to 2, which indicates a strengthened effect of the generation-recombination processes. In the frequency band of dominating 1/f super(m=1) noise, the increase of magnitude of the noise spectral density was proportional to the power of 6, in relation to the current through the detector. This high value is explained as a result of a screening effect of the space charge buildup during the polarization.
ISSN:1748-0221
1748-0221
DOI:10.1088/1748-0221/8/06/C06005