scholarly journals InAs/InAsSb Strain-Balanced Superlattices for Longwave Infrared Detectors

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1907 ◽  
Author(s):  
Tetiana Manyk ◽  
Krystian Michalczewski ◽  
Krzysztof Murawski ◽  
Piotr Martyniuk ◽  
Jaroslaw Rutkowski
Keyword(s):  
Wave Function ◽  
Infrared Detectors ◽  
Theoretical Calculations ◽  
Spectral Response ◽  
Health Condition ◽  
Type Ii ◽  
Response Characteristics ◽  
Effective Masses ◽  
Gaas Substrates ◽  
The Stability

The InAs/InAsSb type-II superlattices (T2SLs) grown on a GaSb buffer layer and GaAs substrates were theoretically investigated. Due to the stability at high operating temperatures, T2SLs could be used for detectors operating in the longwave infrared (LWIR) range for different sensors to include, e.g., CH4 and C2H6 detection, which is very relevant for health condition monitoring. The theoretical calculations were carried out by the 8 × 8 k·p method. The estimated electrons and heavy holes probability distribution in a InAs/InAsSb superlattice (SL) shows that the wave function overlap increases while the thickness of the SL period decreases. The change in the effective masses for electrons and holes versus the SL period thickness for the kz-direction of the Brillouin zone is shown. The structures with a period lower than 15 nm are more optimal for the construction of LWIR detectors based on InAs/InAsSb SLs. The experimental results of InAs/InAsSb T2SLs energy bandgap were found to be comparable with the theoretical one. The proper fitting of theoretically calculated and experimentally measured spectral response characteristics in terms of a strain-balanced and unbalanced structures is shown.

Hole effective masses and subband splitting in type-II superlattice infrared detectors

2016 ◽  
Vol 108 (18) ◽  
pp. 183504 ◽  
Author(s):  
David Z. Ting ◽  
Alexander Soibel ◽  
Sarath D. Gunapala
Keyword(s):  
Infrared Detectors ◽  
Type Ii ◽  
Effective Masses ◽  
Type Ii Superlattice

Uncooled InAs-GaSb type-II infrared detectors grown on GaAs substrates for the 8-12-μm atmospheric window

1999 ◽  
Vol 35 (7) ◽  
pp. 1041-1044 ◽  
Author(s):  
H. Mohseni ◽  
J. Wojkowski ◽  
M. Razeghi ◽  
G. Brown ◽  
W. Mitchel
Keyword(s):  
Infrared Detectors ◽  
Type Ii ◽  
Gaas Substrates ◽  
Atmospheric Window

Predator-dependent transmissible disease spreading in prey under Holling type-II functional response

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dipankar Ghosh ◽  
Prasun K. Santra ◽  
Abdelalim A. Elsadany ◽  
Ghanshaym S. Mahapatra
Keyword(s):  
Functional Response ◽  
Prey Species ◽  
Linearization Method ◽  
Logistic Growth ◽  
Type Ii ◽  
Disease Spreading ◽  
Predator Interactions ◽  
The Stability ◽  
Infected Prey ◽  
Type Ii Functional Response

Abstract This paper focusses on developing two species, where only prey species suffers by a contagious disease. We consider the logistic growth rate of the prey population. The interaction between susceptible prey and infected prey with predator is presumed to be ruled by Holling type II and I functional response, respectively. A healthy prey is infected when it comes in direct contact with infected prey, and we also assume that predator-dependent disease spreads within the system. This research reveals that the transmission of this predator-dependent disease can have critical repercussions for the shaping of prey–predator interactions. The solution of the model is examined in relation to survival, uniqueness and boundedness. The positivity, feasibility and the stability conditions of the fixed points of the system are analysed by applying the linearization method and the Jacobian matrix method.

Novel Fiber-Optic Sensing System for Detection of Methane

2013 ◽  
Vol 562-565 ◽  
pp. 1008-1015 ◽  
Author(s):  
Shu Tao Wang ◽  
Peng Wei Zhang ◽  
Quan Min Zhu
Keyword(s):  
Fiber Optic ◽  
Detection System ◽  
Step Motor ◽  
Harmonic Detection ◽  
Distributed Feedback Laser ◽  
Gas Cell ◽  
Response Characteristics ◽  
The Stability ◽  
Application Fields ◽  
Methane Detection

Based on DFBLD (Distributed Feedback Laser Diode) and harmonic detection technique, a novel fiber-optic methane detection system is constructed. The system can be applied to broad-range concentration detection of methane. Based on the approximation express of the law of Beer-Lambert, detection of methane with various concentration from 0% to 20% is completed using subtraction of background and ratio processing method, as the atmosphere surroundings are treated as background noise. The direct absorption spectra for various concentration is measured using GRIN gas cell, combined with DFBLD. The R5 line of the 2v3 band of methane is selected as the absorption peak. The system is tested online during gas mixing process and the linear relationship between system indication and concentration variation is validated. Also the stability and dynamic response characteristics are confirmed by the experiments. The sensitivity of the system can be adjusted according to the concentration level of various field environments by changing the prism distance using step motor. In the range of 0% to 20% the sensitivity of methane detection can arrive at 0.001%. So the system can be applied to various application fields and adopted as monitoring instruments for coalmine tunnel and natural pipeline.

Low-Lattice-Strain Long-Wavelength GaAsSb/GaInAs Type-II Quantum Wells Grown on GaAs Substrates

2002 ◽  
Vol 41 (Part 2, No. 10A) ◽  
pp. L1040-L1042 ◽  
Author(s):  
Makoto Kudo ◽  
Kiyoshi Ouchi ◽  
Jun-ichi Kasai ◽  
Tomoyoshi Mishima
Keyword(s):  
Quantum Wells ◽  
Lattice Strain ◽  
Type Ii ◽  
Long Wavelength ◽  
Gaas Substrates ◽  
Type Ii Quantum Wells

scholarly journals Carbon Substitution on N24Cages: Crossover between Triangular and Hexagonal Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Carrie Sanders ◽  
Douglas L. Strout
Keyword(s):  
Theoretical Calculations ◽  
High Energy ◽  
Energy Materials ◽  
Cylindrical Structures ◽  
High Energy Materials ◽  
Energy Applications ◽  
Carbon Substitution ◽  
Complex Forms ◽  
The Stability ◽  
Carbon Inclusion

Complex forms of nitrogen are of interest for their potential as high-energy materials, but many all-nitrogen systems lack the stability for practical high-energy applications. Inclusion of carbon atoms in an otherwise all-nitrogen structure can increase stability. Nitrogen cages are known for energetically preferring cylindrical structures with triangular endcaps, but carbon cages prefer the pentagon-hexagon structure of the fullerenes. Previous calculations on N22C2have shown that carbon inclusion narrows the gap between triangular and fullerene-like structures. In the current study, three isomers of N24are used as frameworks for carbon substitution. Theoretical calculations are carried out on isomers of N20C4, N18C6, and N16C8, with the goal of determining what level of carbon substitution causes the carbon fullerene-like structures to become energetically preferred.

scholarly journals Structural Properties of G,T-Parallel Duplexes

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Anna Aviñó ◽  
Elena Cubero ◽  
Raimundo Gargallo ◽  
Carlos González ◽  
Modesto Orozco ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Properties ◽  
Theoretical Calculations ◽  
Md Simulations ◽  
Theoretical Studies ◽  
Duplex Structure ◽  
Strong Stabilization ◽  
The Stability ◽  
The Impact

The structure of G,T-parallel-stranded duplexes of DNA carrying similar amounts of adenine and guanine residues is studied by means of molecular dynamics (MD) simulations and UV- and CD spectroscopies. In addition the impact of the substitution of adenine by 8-aminoadenine and guanine by 8-aminoguanine is analyzed. The presence of 8-aminoadenine and 8-aminoguanine stabilizes the parallel duplex structure. Binding of these oligonucleotides to their target polypyrimidine sequences to form the corresponding G,T-parallel triplex was not observed. Instead, when unmodified parallel-stranded duplexes were mixed with their polypyrimidine target, an interstrand Watson-Crick duplex was formed. As predicted by theoretical calculations parallel-stranded duplexes carrying 8-aminopurines did not bind to their target. The preference for the parallel-duplex over the Watson-Crick antiparallel duplex is attributed to the strong stabilization of the parallel duplex produced by the 8-aminopurines. Theoretical studies show that the isomorphism of the triads is crucial for the stability of the parallel triplex.

scholarly journals INTEGRAL TRANSFORM TECHNIQUE FOR MESON WAVE FUNCTIONS

1996 ◽  
Vol 11 (20) ◽  
pp. 1611-1626 ◽  
Author(s):  
A.P. BAKULEV ◽  
S.V. MIKHAILOV
Keyword(s):  
Wave Function ◽  
Sum Rules ◽  
Integral Transform ◽  
Wave Functions ◽  
Sum Rule ◽  
New Approach ◽  
Exactly Solvable ◽  
The Stability ◽  
The Masses ◽  
Integral Transform Technique

In a recent paper1 we have proposed a new approach for extracting the wave function of the π-meson φπ(x) and the masses and wave functions of its first resonances from the new QCD sum rules for nondiagonal correlators obtained in Ref. 2. Here, we test our approach using an exactly solvable toy model as illustration. We demonstrate the validity of the method and suggest a pure algebraic procedure for extracting the masses and wave functions relating to the case under investigation. We also explore the stability of the procedure under perturbations of the theoretical part of the sum rule. In application to the pion case, this results not only in the mass and wave function of the first resonance (π′), but also in the estimation of π″-mass.

scholarly journals A fibre-based 2D-slit homogenizer concept for high-precision space-based spectrometer missions

2022 ◽  
Author(s):  
Timon Hummel ◽  
Claude Coatantiec ◽  
Xavier Gnata ◽  
Tobias Lamour ◽  
Rémi Rivière ◽  
...  
Keyword(s):  
Spectral Response ◽  
Measurement Data ◽  
Single Fibre ◽  
Study Phase ◽  
Total Size ◽  
The Earth ◽  
Spectral Sample ◽  
Significant Performance ◽  
The Stability ◽  
High Level

AbstractThe measurement accuracy of recent and future space-based imaging spectrometers with a high spectral and spatial resolution suffer from the inhomogeneity of the radiances of the observed Earth scene. The Instrument Spectral Response Function (ISRF) is distorted due to the inhomogeneous illumination from scene heterogeneity. This gives rise to a pseudo-random error on the measured spectra. In order to assess the spectral stability of the spectrograph, stringent requirements are typically defined on the ISRF such as shape knowledge and the stability of the centroid position of the spectral sample. The high level of spectral accuracy is particularly crucial for missions quantifying small variations in the total column of well-mixed trace gases like $$\hbox {CO}_{2}$$ CO 2 . In the framework of the $$\hbox {CO}_{2}$$ CO 2 Monitoring Mission (CO2M) industrial feasibility study (Phase A/B1 study), we investigated a new slit design called 2D-Slit Homogenizer (2DSH). This new concept aims to reduce the Earth scene contrast entering the instrument. The 2DSH is based on optical fibre waveguides assembled in a bundle, which scramble the light in across-track (ACT) and along-track (ALT) direction. A single fibre core dimension in ALT defines the spectral extent of the slit and the dimension in ACT represents the spatial sample of the instrument. The full swath is given by the total size of the adjoined fibres in ACT direction. In this work, we provide experimental measurement data on the stability of representative rectangular core shaped fibre as well as a preliminary pre-development of a 2DSH fibre bundle. In our study, the slit concept has demonstrated significant performance gains in the stability of the ISRF for several extreme high-contrast Earth scenes, achieving a shape stability of $$<0.5{\%}$$ < 0.5 % and a centroid stability of $$<0.25 \ \text {pm}$$ < 0.25 pm (NIR). Given this unprecedented ISRF stabilization, we conclude that the 2DSH concept efficiently desensitizes the instrument for radiometric and spectral errors with respect to the heterogeneity of the Earth scene radiance.

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