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Proceedings Paper

Increased responsivity and detectivity in asymmetric quantum-well infrared detectors
Author(s): Abraham Fraenkel; A. Brandel; Gad Bahir; Elieser Finkman; Gabriela Livescu; Moses T. Asom
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Paper Abstract

A new type of asymmetric stepped GaAs/AlGaAs multi quantum well infrared detectors is reported. These asymmetric detectors utilize the usual bound to continuum transition. The current responsivity is remarkably asymmetric with regard to the voltage polarity. In contrast with rectangular wells, in which responsivity is saturated in both bias polarities, these wells exhibit saturation only for negative bias. The responsivity increases monotonously with positive electric field. The difference between polarities for the noise is much smaller at low temperatures. As a result, the highest D* in positive polarity is much higher than in the negative one. This is attributed to changes induced by the field on the transport properties of the excited electrons. In particular, the bias affects the dwell time spent by the carrier wave packet in the well region. Employing this model, we achieve a very good fit with experimental data. The transport asymmetry is further studied using identical asymmetric wells which were grown in opposite sequences. It is shown that the effect of the asymmetry in the interfaces is of the same order of magnitude as the structural asymmetry.

Paper Details

Date Published: 10 December 1992
PDF: 11 pages
Proc. SPIE 1735, Infrared Detectors: State of the Art, (10 December 1992); doi: 10.1117/12.138627
Show Author Affiliations
Abraham Fraenkel, Technion--Israel Institute of Technology (Israel)
A. Brandel, Technion--Israel Institute of Technology (Israel)
Gad Bahir, Technion--Israel Institute of Technology (Israel)
Elieser Finkman, Technion--Israel Institute of Technology (Israel)
Gabriela Livescu, AT&T Bell Labs. (United States)
Moses T. Asom, AT&T Bell Labs. (United States)

Published in SPIE Proceedings Vol. 1735:
Infrared Detectors: State of the Art
Wagih H. Makky, Editor(s)

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