Special Section on Infrared Systems

Modeling of midwavelength infrared InAs/GaSb type II superlattice detectors

[+] Author Affiliations
Piotr Martyniuk, Jarosław Wróbel, Paweł Madejczyk, Waldemar Gawron, Andrzej Kowalewski, Antoni Rogalski

Military University of Technology, Institute of Applied Physics, 2 Kaliskiego Street, 00-908 Warsaw, Poland

Elena Plis, Sanjay Krishna

University of New Mexico, Center for High Technology Materials, Department of Electrical and Computer Engineering, Albuquerque, New Mexico 87106

Opt. Eng. 52(6), 061307 (Jan 31, 2013). doi:10.1117/1.OE.52.6.061307
History: Received July 10, 2012; Revised December 6, 2012; Accepted December 28, 2012
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Abstract.  The performance of midwavelength infrared type II superllatice InAs/GaSb PIN and nBn (AlGaSb barrier) photodetectors in a reverse bias voltage range and a temperature range from 77 to 240 K is described. The PIN and nBn structures are modeled by a bulk based model, i.e., type II superllatice is treated as an artificial semiconductor material where parameters describing its physical properties are extracted from the experimental data. The model assumes that position of the effective trap energy level depends on temperature, what allowed to obtain a very good fitting to the measurements. Temperature and bias dependent dark current and differential resistance area product of the both devices have been analyzed to investigate contributing mechanisms such as: diffusion, generation-recombination, band-to-band and trap-assisted tunneling that limit the electrical performance of both types of the detectors. The IV and RA(V) product characteristics of both types of type II superllatice InAs/GaSb photodetectors were found to be dominated by diffusion and generation-recombination currents in the nearly zero-bias region. At medium values of reverse bias, the trap-assisted tunneling reveals its significance, while at higher reverse voltages—the band-to-band tunneling is decisive to IV and RA(V) characteristics. The fitting procedure allowed to extract both generation-recombination and diffusion components of carrier lifetimes pointing out that the carrier lifetimes range from 2 to 10 ns at T=200K. Detectivity for T=240K and V=50mV was estimated to be 109cmHz1/2/W and 4×109cmHz1/2/W for PIN and nBn detector, respectively. Finally, type II superlattice InAs/GaSb PIN and nBn structures’ performance is compared to both unipolar barrier nBn HgCdTe detector and bulk HgCdTe photodiodes operated at near-room temperature. It is shown that the performance of SL and HgCdTe photo detectors with a cut-off of about 5 μm is comparable at operation temperatures around 240 K.

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© 2013 Society of Photo-Optical Instrumentation Engineers


Piotr Martyniuk ; Jarosław Wróbel ; Elena Plis ; Paweł Madejczyk ; Waldemar Gawron, et al.
"Modeling of midwavelength infrared InAs/GaSb type II superlattice detectors", Opt. Eng. 52(6), 061307 (Jan 31, 2013). ; http://dx.doi.org/10.1117/1.OE.52.6.061307

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