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Optical Engineering

Investigation for optoelectronic characteristics and imaging performance of InAs quantum dot covered with In0.1Ga0.9As/GaAs multilayer based focal plane array
Author(s): Tzu-Chiang Chen; Jian-Hao Lai
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Paper Abstract

We report on a structure prepared by metalorganic chemical vapor deposition and molecular beam epitaxy techniques incorporated with a standard process of compound semiconductor to achieve In0.1Ga0.9As/InAs/In0.1Ga0.9As quantum dot infrared photodetector (QDIP)-based focal plane array. For investigating the mechanism of carrier transport and optoelectronic behavior, the photoresponse spectra and dark current were measured in agreement with the theoretical simulations. Furthermore, a model is proposed with the systematic analyses and explained for designing high-performance QDIPs based on the calculations of thermal activation energy and detectivity. For QDIP photoresponse measurements, the photovoltaic photoresponse is achieved, which can be attributed to the asymmetric morphology of quantum dot epitaxy. With increasing bias, the photoresponse spectra exhibit a redshift due to band bending that generates a thinner triangle barrier which increases the escape possibility of the excited carriers situated at lower excited-state levels. The trapezoid-edged scheme enhances infrared coupling and increases the photoresponse intensity. A single-sided gradient AlxGa1-xAs (x = 0.25→0) barrier can suppress the dark-current under bias efficiently. The infrared imaging performance of InGaAs QDIP based on 320×256 FPA is also demonstrated in this paper.

Paper Details

Date Published: 1 June 2011
PDF: 7 pages
Opt. Eng. 50(6) 061004 doi: 10.1117/1.3572146
Published in: Optical Engineering Volume 50, Issue 6
Show Author Affiliations
Tzu-Chiang Chen, National Defense Univ. (Taiwan)
Jian-Hao Lai, National Defense Univ. (Taiwan)

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