Interdiffusion Effects on Bandstructure in HgTe-CdTe Superlattices for VLWIR Imaging Applications

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Abstract

In this paper, a systematic study of interdiffusion in (112)B oriented HgTe/CdTe superlattice (SL) structures has been undertaken in order to investigate the viability of employing SL as the absorber layer for very long wavelength infrared (VLWIR, 15 μm and longer) applications in imaging focal plane arrays. Using numerical analysis, the optimal superlattice parameters and annealing time at the growth temperature (∼ 180°C) are found, which result in better control of the cut-off wavelength in superlattice absorbers compared to the corresponding HgCdTe alloy absorber. Simulations show that, by appropriate adjustment of annealing time, it is possible to achieve the same cut-off wavelength with a larger HgTe well width while the sensitivity of the SL to well width variations remains at 15 meV/nm. Furthermore, the electron effective mass in a SL absorber is larger than a HgCdTe alloy absorber, which results in lower tunneling dark current. This work focuses on optimization of the superlattice absorber using the stationary Schrödinger equation. A complete photodetector device design based on a SL absorber structure will require a comprehensive numerical modeling using a Schrödinger–Poisson solver and drift–diffusion solver, or a combination of both approaches, which will be undertaken in the future.

Original languageEnglish
JournalJournal of Electronic Materials
DOIs
Publication statusE-pub ahead of print - 20 Jun 2019

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Superlattices
superlattices
absorbers
Imaging techniques
Wavelength
Annealing
Focal plane arrays
Dark currents
Growth temperature
Photodetectors
Numerical analysis
cut-off
Infrared radiation
wavelengths
Electrons
annealing
focal plane devices
dark current
viability
numerical analysis

Cite this

@article{60faf8b2d56a46d299e0c0e22cbcf982,
title = "Interdiffusion Effects on Bandstructure in HgTe-CdTe Superlattices for VLWIR Imaging Applications",
abstract = "In this paper, a systematic study of interdiffusion in (112)B oriented HgTe/CdTe superlattice (SL) structures has been undertaken in order to investigate the viability of employing SL as the absorber layer for very long wavelength infrared (VLWIR, 15 μm and longer) applications in imaging focal plane arrays. Using numerical analysis, the optimal superlattice parameters and annealing time at the growth temperature (∼ 180°C) are found, which result in better control of the cut-off wavelength in superlattice absorbers compared to the corresponding HgCdTe alloy absorber. Simulations show that, by appropriate adjustment of annealing time, it is possible to achieve the same cut-off wavelength with a larger HgTe well width while the sensitivity of the SL to well width variations remains at 15 meV/nm. Furthermore, the electron effective mass in a SL absorber is larger than a HgCdTe alloy absorber, which results in lower tunneling dark current. This work focuses on optimization of the superlattice absorber using the stationary Schr{\"o}dinger equation. A complete photodetector device design based on a SL absorber structure will require a comprehensive numerical modeling using a Schr{\"o}dinger–Poisson solver and drift–diffusion solver, or a combination of both approaches, which will be undertaken in the future.",
keywords = "8 × 8 k.p Hamiltonian, diffusion equation, HgCdTe alloy, HgTe/CdTe superlattice, infrared photodetector, interdiffusion",
author = "Akhavan, {N. D.} and Umana-Membreno, {G. A.} and R. Gu and J. Antoszewski and L. Faraone",
year = "2019",
month = "6",
day = "20",
doi = "10.1007/s11664-019-07353-w",
language = "English",
journal = "Journal of Electronic Materials",
issn = "0361-5235",
publisher = "Springer",

}

TY - JOUR

T1 - Interdiffusion Effects on Bandstructure in HgTe-CdTe Superlattices for VLWIR Imaging Applications

AU - Akhavan, N. D.

AU - Umana-Membreno, G. A.

AU - Gu, R.

AU - Antoszewski, J.

AU - Faraone, L.

PY - 2019/6/20

Y1 - 2019/6/20

N2 - In this paper, a systematic study of interdiffusion in (112)B oriented HgTe/CdTe superlattice (SL) structures has been undertaken in order to investigate the viability of employing SL as the absorber layer for very long wavelength infrared (VLWIR, 15 μm and longer) applications in imaging focal plane arrays. Using numerical analysis, the optimal superlattice parameters and annealing time at the growth temperature (∼ 180°C) are found, which result in better control of the cut-off wavelength in superlattice absorbers compared to the corresponding HgCdTe alloy absorber. Simulations show that, by appropriate adjustment of annealing time, it is possible to achieve the same cut-off wavelength with a larger HgTe well width while the sensitivity of the SL to well width variations remains at 15 meV/nm. Furthermore, the electron effective mass in a SL absorber is larger than a HgCdTe alloy absorber, which results in lower tunneling dark current. This work focuses on optimization of the superlattice absorber using the stationary Schrödinger equation. A complete photodetector device design based on a SL absorber structure will require a comprehensive numerical modeling using a Schrödinger–Poisson solver and drift–diffusion solver, or a combination of both approaches, which will be undertaken in the future.

AB - In this paper, a systematic study of interdiffusion in (112)B oriented HgTe/CdTe superlattice (SL) structures has been undertaken in order to investigate the viability of employing SL as the absorber layer for very long wavelength infrared (VLWIR, 15 μm and longer) applications in imaging focal plane arrays. Using numerical analysis, the optimal superlattice parameters and annealing time at the growth temperature (∼ 180°C) are found, which result in better control of the cut-off wavelength in superlattice absorbers compared to the corresponding HgCdTe alloy absorber. Simulations show that, by appropriate adjustment of annealing time, it is possible to achieve the same cut-off wavelength with a larger HgTe well width while the sensitivity of the SL to well width variations remains at 15 meV/nm. Furthermore, the electron effective mass in a SL absorber is larger than a HgCdTe alloy absorber, which results in lower tunneling dark current. This work focuses on optimization of the superlattice absorber using the stationary Schrödinger equation. A complete photodetector device design based on a SL absorber structure will require a comprehensive numerical modeling using a Schrödinger–Poisson solver and drift–diffusion solver, or a combination of both approaches, which will be undertaken in the future.

KW - 8 × 8 k.p Hamiltonian

KW - diffusion equation

KW - HgCdTe alloy

KW - HgTe/CdTe superlattice

KW - infrared photodetector

KW - interdiffusion

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