Identification of a limiting mechanism in GaSb-rich superlattice midwave infrared detector

Delmas, M.; Rodriguez, J. B.; Rossignol, R.; Licht, Abigail; Giard, E.; Ribet-Mohamed, I.; Christol, Philippe

doi:10.1063/1.4948670

Cited by 6 publications

(5 citation statements)

References 30 publications

(41 reference statements)

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“…Of these, the trap-assisted tunnelling is the most important. In particular, this current may dominate over btb current in the SL devices doped below 1•10 17 cm −3 [48]. So, the oscillations in the current-voltage characteristics predicted by the analyses performed in this paper can be observed only in the devices made of high-quality materials, in which the trap-mediated tunnelling components are lower than the direct btb component [43][44][45][46][47].…”

Section: Discussionmentioning

confidence: 66%

“…In simplified drift-diffusion (DD) approaches, the SL material is often replaced with some equivalent (bulk) material that has parameters derived from SL properties [48][49][50][51]. Namely, its bandgap is defined as the energy difference between the lower edge of miniband C1 and the valid approximately for the minibands (in the growth direction), the masses can be further related to miniband widths, WC1/H1.…”

Section: Virtual Materials Approximationmentioning

confidence: 99%

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Quantum simulations of band-to-band tunnelling in a type-II broken-gap superlattice diode

2024

Opto-Electronics Review

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In recent years, type-II superlattice-based devices have completed the offer of the electronic industry in many areas of applications. Photodetection is one of them, especially in the midinfrared wavelength range. It is due to the unique feature of a superlattice material, which is a tuneable bandgap. It is also believed that the dark current of superlattice-based photodetectors is strongly suppressed due to the suppression of the band-to-band tunnelling current in a superlattice material. This argument relies, however, on a semi-classical approach that treats superlattice as a bulk material with effective parameters extracted from the kp analysis. In the paper, a superlattice device is analysed on a quantum level: the nonequilibrium Green's function method is applied to the two-band Hamiltonian of the InAs/GaSb superlattice p-i-n diode. The analysis concentrates on the band-to-band tunnelling with the aim to validate the correctness of a semi-classical description of the phenomenon. The results of calculations reveal that in a superlattice diode, the inter-band tunnelling occurs only for certain values of energy and in-plane momentum, for which electronic and hole sub-bands cross. The transitions occurring for vanishing in-plane momentum produce resonances in the current-voltage characteristics -the feature which was reported in a few experimental observations. This scenario is quite different from that occurring in bulk materials, where there is a range of energy-momentum pairs for which the band-to-band tunnelling takes place, and so current-voltage characteristics are free from any resonances. However, simulations show that, while not justified for a detailed analysis, the semi-classical description can be applied to superlattice-based devices for an 'order of magnitude' estimation of the band-to-band tunnelling current.

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Section: Discussionmentioning

confidence: 66%

Section: Virtual Materials Approximationmentioning

confidence: 99%

Quantum simulations of band-to-band tunnelling in a type-II broken-gap superlattice diode

2024

Opto-Electronics Review

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“…3 Secondly, the intrinsic carrier density n i is also an important parameter affecting the dark current density induced by the Shockley-Read-Hall (SRH) recombination mechanism. 10,20) We thus evaluated the intrinsic carrier density at 77 K from n i = (np) 1/2 , where n and p are the electron and hole concentration, respectively, which were numerically calculated from 21) ò r…”

Section: Sl Period Dependence Of Band Structurementioning

confidence: 99%

Evaluation of the optical characteristics of a type-II InAs/GaSb superlattice infrared p–i–n photodetector

Thi¹,

Kamakura²,

Mori³

2019

Jpn. J. Appl. Phys.

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We investigated the characteristics of a type-II InAs/GaSb superlattice (SL) with various composition periods based on the k·p band calculation. Considering the application to the infrared photodetectors, the essential material parameters are calculated and evaluated from the electronic band structure as a function of the width of InAs and GaSb layers. Under dark conditions, the smaller effective mass in a short period SL (especially with small GaSb layer width) could result in the reduction of the Shockley–Read–Hall (SRH) leakage current which is proportional to the intrinsic carrier density. However, this merit is also concerned with the increase of the dark current due to the enhanced band-to-band tunneling in high electric field conditions. Moreover, in terms of the photo-absorption property, the smaller effective mass results in the smaller joint density of states, which compensates the contribution of the large optical matrix element to the absorption coefficient in short period SL.

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“…9) So far, device simulations have been demonstrated for p-i-n photodiodes with InAs/GaSb SL layer, and the dark current properties were intensively investigated. 2,6,11,12,13) However, the essential input material parameters were calculated as a weighted average of InAs and GaSb bulk values, like the electron affinity, the permittivity, the effective mass, and the mobility. 9,10) In this work, we are aiming to develop a simulation framework to estimate the characteristics of the SL-based photodiodes.…”

Section: Introductionmentioning

confidence: 99%

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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Identification of a limiting mechanism in GaSb-rich superlattice midwave infrared detector

Cited by 6 publications

References 30 publications

Quantum simulations of band-to-band tunnelling in a type-II broken-gap superlattice diode

Quantum simulations of band-to-band tunnelling in a type-II broken-gap superlattice diode

Evaluation of the optical characteristics of a type-II InAs/GaSb superlattice infrared p–i–n photodetector

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

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