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Progress in Symmetric and Asymmetric Superlattice Quantum Well Infrared Photodetectors
Author(s) -
Penello Germano M.,
Pereira Pedro H.,
Guerra Lesslie,
Pinto Luciana D.,
Jakomin Roberto,
Mourão Renato T.,
Degani Marcos H.,
Maialle Marcelo Z.,
Sivco Deborah,
Gmachl Claire,
Pires Mauricio P.,
Souza Patricia L.
Publication year - 2019
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201800462
Subject(s) - superlattice , quantum well infrared photodetector , quantum well , infrared , photodetection , physics , condensed matter physics , photodetector , optoelectronics , semiconductor , far infrared , materials science , optics , laser
Herein, two challenges are addressed, which quantum well infrared photodetectors (QWIPs), based on III‐V semiconductors, face, namely: photodetection within the so‐called “forbidden gap”, between 1.7 and 2.5 microns, and room temperature operation using thermal sources. First, to reach this forbidden wavelength range, a QWIP which consists of a superlattice structure with a central quantum well (QW) with a different thickness is presented. The different QW in the symmetric structure, which plays the role of a defect in the otherwise periodic structure, gives rise to localized states in the continuum. The proposed InGaAs/InAlAs superlattice QWIP detects radiation around 2.1 microns, beyond the materials bandoffset. Additionally, the wavefunction parity anomaly is explored to increase the oscillator strength of the optical transitions involving higher order states. Second, with the purpose of achieving room temperature operation, an asymmetric InGaAs/InAlAs superlattice, in which the QW with a different thickness is not in the center, is used to detect infrared radiation around 4 microns at 300 K. This structure operates in the photovoltaic mode because it gives rise to states in the continuum which are localized in one direction and extended in the other, leading to a preferential direction for current flow.