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Advances in Condensed Matter Physics
Volume 2015, Article ID 306912, 5 pages
http://dx.doi.org/10.1155/2015/306912
Research Article

Photoresponse of Long-Wavelength AlGaAs/GaAs Quantum Cascade Detectors

1Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, China
2Shanghai Key Laboratory of Multidimensional Information Processing, East China Normal University, Shanghai 200241, China

Received 27 November 2014; Accepted 4 January 2015

Academic Editor: Wen Lei

Copyright © 2015 Liang Li and Dayuan Xiong. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We study the photoresponse and photocurrents of long-wavelength infrared quantum cascade detectors (QCDs) based on AlGaAs/GaAs material system. The photocurrent spectra were measured at different temperatures from 20 K to 100 K with a low noise Fourier transforming infrared spectrometer. The main response peak appeared at 8.9 μm while four additional response peaks from 4.5 μm to 10.1 μm were observed as well. We confirmed that the photocurrent comes from phonon assisted tunneling and the multipeak behavior comes from the complicated optical transition in the quantum cascade structure. This work is valuable for the future design and optimization of QCD devices.