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    Rights statement: Veronica Letka, James Keen, Adam Craig, and Andrew R. J. Marshall "Modelling and measurement of bandgap behaviour in medium-wavelength IR InAs/InAs0.815Sb0.185 strained-layer superlattices", Proc. SPIE 10433, Electro-Optical and Infrared Systems: Technology and Applications XIV, 1043319 (6 October 2017); https://doi.org/10.1117/12.2278733 Copyright 2017 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

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Modelling and measurement of bandgap behaviour in medium-wavelength IR InAs/InAs0.815Sb0.185 strained-layer superlattices

Research output: Contribution to journalJournal article

Published
Article number1043319
<mark>Journal publication date</mark>6/10/2017
<mark>Journal</mark>Proceedings of SPIE - The International Society for Optical Engineering
Volume10433
Number of pages7
Publication StatusPublished
<mark>Original language</mark>English
EventElectro-Optical and Infrared Systems: Technology and Applications XIV 2017 - Warsaw, Poland
Duration: 13/09/201714/09/2017

Conference

ConferenceElectro-Optical and Infrared Systems: Technology and Applications XIV 2017
CountryPoland
CityWarsaw
Period13/09/1714/09/17

Abstract

InAs/InAs1-xSbx type-II strained-layer superlattices (SLS) are a structure with potential infrared detection applications, owing to its tunable bandgap and suppressed Auger recombination. A series of medium-wavelength infrared (MWIR) InAs/InAs0.815Sb0.185 SLS structures, grown as undoped absorption epilayers on GaAs, were fabricated using molecular beam epitaxy in order to study the dependence of the ground state transitions on temperature and superlattice period thickness. Photoluminescence peaks at 4 K were obtained with the use of a helium-cooled micro-PL system and an InSb detector, and temperature-dependent absorption spectra were measured in the range 77 K-300 K on a Fourier Transform Infrared (FTIR) spectrometer, equipped with a 1370 K blackbody source and a DTGS detector. An nBn device sample with the absorber structure identical to one of the undoped samples was also grown and processed with the goal of measuring temperature-dependent spectral response. A model for superlattice band alignment was also devised, incorporating the Bir-Pikus transformation results for uniaxial and biaxial strain, and the Einstein oscillator model for bandgap temperature dependence. Absorption coefficients of several 1000 cm-1 throughout the entire MWIR range are found for all samples, and temperature dependence of the bandgaps is extracted and compared to the model. This and photoluminescence data also demonstrate bandgap shifts consistent with the different superlattice periods of the three samples.

Bibliographic note

Veronica Letka, James Keen, Adam Craig, and Andrew R. J. Marshall "Modelling and measurement of bandgap behaviour in medium-wavelength IR InAs/InAs0.815Sb0.185 strained-layer superlattices", Proc. SPIE 10433, Electro-Optical and Infrared Systems: Technology and Applications XIV, 1043319 (6 October 2017); https://doi.org/10.1117/12.2278733 Copyright 2017 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.