Effect of microscopic interface asymmetry on optical properties of short-period InAs/GaSb type-II superlattices

Dong, H. M.; Li, L.L.; Xu, W.; Han, Kui

doi:10.1016/j.tsf.2015.05.066

Cited by 9 publications

(13 citation statements)

References 34 publications

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“…In order to explain the shape of the absorption curves in a wider photon energy range, it is necessary to consider the polarization of the light [24]. Figure 7 shows α for both transverse electronic (TE) and transverse magnetic (TM) mode in the LWIR region for two different SL periods equal to L = 14.5 nm and L = 25 nm.…”

Section: Resultsmentioning

confidence: 99%

InAs/InAsSb Strain-Balanced Superlattices for Longwave Infrared Detectors

Manyk

Michalczewski

Murawski

et al. 2019

Sensors

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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.

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Section: Resultsmentioning

confidence: 99%

InAs/InAsSb Strain-Balanced Superlattices for Longwave Infrared Detectors

Manyk

Michalczewski

Murawski

et al. 2019

Sensors

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“…Therefore, to analyze the experimental data, the microscopic interface asymmetry (MIA) effect has been introduced in the the k•p band calculation. [18][19][20] Then, the total Hamiltonian is expressed as…”

Section: K•p Band Calculationmentioning

confidence: 99%

“…In this study, to reproduce this observation, we have adjusted the interface potential parameter H t (InSb) to 0.58 eV, while the other parameters used in the k•p calculation were the same as those given in Ref. 20.…”

Section: K•p Band Calculationmentioning

confidence: 99%

“…In practice, the interfaces often turn out to be mixed and interdiffused, depending on growth conditions and degree of growth control, 22) and the interface potential energies were treated as fitting parameters. 20) In this study, to fit the experimental data of Ref. 9, we employed H t (InSb) = 0.58 eV, which is of the same magnitude as previous works.…”

Section: K•p Band Calculationmentioning

confidence: 99%

“…For comparison, the band gap energies and effective masses calculated without the MIA effect are also shown, indicating that the MIA effect reduces m z,h as well as E g . 20) The other parameters such as the permittivity and the mobility were determined from the weighted average of InAs and GaSb bulk values, 10) which are summarized in Table II.…”

Section: Extraction Of Parameters For Device Simulationmentioning

confidence: 99%

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Simulation of dark current characteristics of type-II InAs/GaSb superlattice mid-wavelength infrared p–i–n photodetector

Thi

Kamakura

Mori

2019

Jpn. J. Appl. Phys.

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For photosensitive devices such as infrared (IR) photodetectors, dark current is an important mechanism limiting the performance because it causes a decrease in the signal-to-noise ratio and the responsivity. The main objective of this work is to understand and analyze the InAs/GaSb type-II superlattice (SL) IR photodiode using a device simulator especially focusing on the dark current characteristics. Physical parameters such as the effective density of states and the effective masses are extracted from the k•p band calculation, and included into a two-dimensional device simulator based on the drift-diffusion model. Simulation results demonstrate that the leakage current of the IR photodiode depends on the SL thickness ratio even with the same cut-off wavelength. In the low reverse bias conditions, the "InAs-rich" SL detectors exhibit smaller dark current than the "GaSb-rich" ones, which originates from the difference in the intrinsic carrier density. On the other hand, under the higher voltage and the higher doping level, the larger effective mass of "GaSb-rich" SL can suppress the dark current caused by the tunneling-related leakage mechanisms. © 2019 The Japan Society of Applied Physicswhere z is the position along the SL growth direction, H t (InSb) and H t (GaAs) are the fitting parameters for the strength of the potential at InSb-like and GaAs-like interfaces, a 0 is the lattice constant of GaSb, and ii Q ¢ is given by

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Theory and optimisation of radiative recombination in broken-gap InAs/GaSb superlattices

Murphy,

O’Reilly,

Broderick

2023

J. Phys. D: Appl. Phys.

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We present a theoretical analysis of mid-infrared radiative recombination in InAs/GaSb superlattices (SLs). We employ a semi-analytical plane wave expansion method in conjunction with an 8-band k·p Hamiltonian to compute the SL electronic structure, paying careful attention to the identification and mitigation of spurious solutions. The calculated SL eigenstates are used directly to compute spontaneous emission spectra and the radiative recombination coefficient B. We elucidate the origin of the relatively large B coefficients in InAs/GaSb SLs which, despite the presence of spatiallyindirect (type-II-like) carrier confinement, are close to that of bulk InAs and compare favourably to those calculated for mid-infrared type-I pseudomorphic and metamorphic quantum well structures having comparable emission wavelengths. Our analysis explicitly quantifies the roles played by carrier localisation (specifically, partial delocalisation of bound electron states) and miniband formation (specifically, miniband occupation and optical selection rules) in determining the magnitude of B and its temperature dependence. We perform a high-throughput optimisation of the room temperature B coefficient in InAs/GaSb SLs across the 3.5 – 7 μm wavelength range, quantifying the dependence of B on the relative thickness of the electron-confining InAs and hole-confining GaSb layers. This analysis provides guidance for the growth of optimised SLs for mid-infrared light emitters. Our results, combined with the expected low non-radiative Auger recombination rates in structures having spatially indirect electron and hole confinement, corroborate recently observed high output power in prototype InAs/GaSb SL inter-band cascade light-emitting diodes.

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Effect of microscopic interface asymmetry on optical properties of short-period InAs/GaSb type-II superlattices

Cited by 9 publications

References 34 publications

InAs/InAsSb Strain-Balanced Superlattices for Longwave Infrared Detectors

InAs/InAsSb Strain-Balanced Superlattices for Longwave Infrared Detectors

Simulation of dark current characteristics of type-II InAs/GaSb superlattice mid-wavelength infrared p–i–n photodetector

Theory and optimisation of radiative recombination in broken-gap InAs/GaSb superlattices

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