Response time of the type-II superlattice InAs/InAsSb mid-infrared interband cascade photodetector for HOT conditions
Journal
Optics & Laser Technology
Journal Volume
182
Start Page
112172
ISSN
0030-3992
Date Issued
2025-04
Author(s)
Karol Dąbrowski
Waldemar Gawron
Łukasz Kubiszyn
Bartłomiej Seredyński
Krystian Michalczewski
Piotr Martyniuk
Abstract
The article presents III-V InAs/InAsSb type-II superlattice (T2SL) mid-wave infrared (MWIR, 100 % cut-off wavelength, λcut-off ∼ 7.5 μm at 333 K) interband cascade photodetector (ICIP) developed to operate at temperatures > 300 K. That device solves the low quantum efficiency (QE) problem of the typical “thick absorber” photodetectors designed for high operating temperature (HOT, > 300 K) conditions. The 5-stage epilayer was grown by molecular beam epitaxy (MBE) on the lattice-mismatched GaAs substrates where absorbers are connected by the highly doped standard n+/p+ tunnel junctions. The developed and analyzed high-speed MWIR devices should be implemented in the emerging fields such as frequency comb spectroscopy (FCS), free space optical communication (FSO) and light detection and ranging (LIDAR). The majority of the MWIR ICIPs’ research have been focused on the QE increase and dark current suppressing to improve the detectivity (D*) while the high- frequency operation (HFO) is still not completely investigated. We report on the MWIR InAs/InAsSb T2SLs ICIP where tradeoff between response time and detectivity was obtained. The time constant being limited by the carriers’ transit time reaches ∼ 16 ns corresponding to 3-dB bandwidth, f3-dB ∼ 10 MHz (detectivity ∼ 2 × 108 cmHz1/2/W without immersion GaAs lens with ∼ 0.53 μm single absorber) for λcut-off ∼ 7.5 μm at 333 K and unbiased conditions. Under 1 V time constant reaches ∼ 2.4 ns (f3-dB ∼ 66 MHz).
Publisher
Elsevier BV
Type
journal article