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Proceedings Paper

Some features of gain and detectivity frequency dependencies of low-background extrinsic IR detectors
Author(s): Nicolas B. Zaletaev
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Paper Abstract

Experimental and theoretical studies of low-background behavior of extrinsic photoconductor detectors (EPDs) with a steady-state photoconductive gain G>1 and extrinsic double-injection photodiodes (EDIPs) were carried out. In both the cases, frequency response had two plateaus. It was established that four regions with various values of theoretical background limit of detectivity can be distinguished in the frequency range of EPDs. Temperature dependence of the 3-db cutoff frequency of low-frequency (LF) plateau for Si:Ga EPDs was found not to be described by existing models. This characteristic frequency sharply decreased with decreasing temperature (T<20K, background- limited current) and then became weakly dependent on temperature below 12 K. A model explaining this phenomenon through peculiarities of contact injection has been suggested. The responsivity of Ge:Hg EDIPs reached 2000 A/W, which corresponded to a gain of about 1000, and was about two orders of magnitude higher than that for EPDs of the same material. The ultimate detectivity in this case, nevertheless, was close to that of EPDs and the gain- bandwidth product was much greater. The decay segment between two plateaus on frequency response curve of EDIPs is more extended than that of EPDs, which is conditioned by great gain value for EDIPs. The high-frequency plateau of the curve is due to the displacement current, similar to EPD case, and the detectivity limit here is gain-dependent and lower than that for LF part of the curve, as well.

Paper Details

Date Published: 15 December 2000
PDF: 12 pages
Proc. SPIE 4130, Infrared Technology and Applications XXVI, (15 December 2000); doi: 10.1117/12.409837
Show Author Affiliations
Nicolas B. Zaletaev, Research, Development, and Production Ctr. ORION (Russia)

Published in SPIE Proceedings Vol. 4130:
Infrared Technology and Applications XXVI
Bjorn F. Andresen; Gabor F. Fulop; Marija Strojnik, Editor(s)

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