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Proceedings Paper

Focal plane arrays based on quantum dot infrared photodetectors
Author(s): Manijeh Razeghi; Wei Zhang; Ho-Chul Lim; Stanley Tsao; John Szafraniec; Maho Taguchi; Bijan Movaghar
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Paper Abstract

Here we report the first demonstrations of infrared focal plane array (FPA) based on GaAs and InP based quantum dot infrared photodetectors (QDIPs). QDIPs are extension of quantum well infrared photodetectors (QWIPs) and are predicted to outperform QWIPs due to their potential advantages including normally incident absorption, higher responsivity and high temperature operation. Two material systems have been studied: InGaAs/InGaP QDIPs on GaAs substrates and InAs QDIP on InP substrates. An InGaAs/InGaP QDIP has been grown on GaAs substrate by LP-MOCVD. Photoresponse was observed at temperatures up to 200 K with a peak wavelength of 4.7 μm and cutoff wavelength of 5.2 μm. A detectivity of 1.2x1011 cmHz1/2/W was obtained at T=77 K and bias of -0.9 V, which is the highest for QDIPs grown by MOCVD. An InAs QDIP structure has also been grown on InP substrate by LP-MOCVD. Photoresponse of normal incidence was observed at temperature up to 160K with a peak wavelength of 6.4 μm and cutoff wavelength of 6.6 μm. A detectivity of 1.0x1010 cmHz1/2/W was obtained at 77K at biases of -1.1 V, which is the first and highest detectivity reported for QDIP on InP substrate. 256×256 detector arrays were fabricated first time in the world for both the GaAs and InP based QDIPs. Dry etching and indium bump bonding were used to hybridize the arrays to a Litton readout integrated circuit. For the InGaAs/InGaP QDIP FPA, thermal imaging was achieved at temperatures up to 120 K. At T=77K, the noise equivalent temperature difference (NEDT) was measured as 0.509K with a 300K background and f/2.3 optics. For the InP based QDIPs, thermal imaging was achieved at 77 K.

Paper Details

Date Published: 28 June 2005
PDF: 12 pages
Proc. SPIE 5838, Nanotechnology II, (28 June 2005); doi: 10.1117/12.607534
Show Author Affiliations
Manijeh Razeghi, Northwestern Univ. (United States)
Wei Zhang, Northwestern Univ. (United States)
Ho-Chul Lim, Northwestern Univ. (United States)
Stanley Tsao, Northwestern Univ. (United States)
John Szafraniec, Northwestern Univ. (United States)
Maho Taguchi, Northwestern Univ. (United States)
Bijan Movaghar, Northwestern Univ. (United States)


Published in SPIE Proceedings Vol. 5838:
Nanotechnology II
Paolo Lugli; Laszlo B. Kish; Javier Mateos, Editor(s)

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