Impact of donor compensation ratio on photorefractive two–wave mixing dynamics in multiple quantum wells structures

Jabłoński, Błażej

doi:10.1142/s0218863514500295

Cited by 2 publications

(2 citation statements)

References 12 publications

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“…where , define the electron mobility in the central and side valleys, while is a distribution function expressing relative occupation of the central valley [7].…”

Section: West Pomeranian University Of Technology In Szczecin Piastómentioning

confidence: 99%

The impact of electron and hole trapping coefficient on nonlinear phenomena in photorefractive multiple quantum well structures

Jabłoński

Ziółkowski

Branecka

et al. 2016

Photon. Lett. Poland

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Abstract-Semiconductor photorefractive quantum wells belong to materials with strong optical nonlinearity. One of the parameters that may affect the course of nonlinear phenomena in these materials is the electron and hole trapping coefficient. We present the results of a numerical analysis aimed to find out how electric field-dependent trapping coefficients affect the process of space-charge field formation in multiple quantum wells in the phenomenon of photorefractive twowave mixing.Photorefractive multiple quantum wells are characterized by high sensitivity and relatively short response time [1][2]. A characteristic feature of these materials is the occurrence of bipolar transport. This reduces the impact of diffusion on the phenomenon and necessitates the application of an external electric field. For GaAs/AlGaAs structures working in Franz-Keldysh geometry (electric field applied parallel to quantum wells), it is observed that electron mobility depends on field intensity. This phenomenon affects the course of two-wave mixing, causing the shift of a space-charge field relative to the interference pattern and enabling oneway exchange of energy between the waves [1][2][3].Another parameter that may have an impact on the course of nonlinear phenomena is the electron and hole trapping coefficient. The study [5] presents the influence of a strong electric field on the values of cross-sections for recombination to traps for bulk GaAs with EL2 defects. On the other hand, in studies of photorefractive two-wave mixing in GaAs/AlGaAs quantum wells the authors adopt a fixed value of these coefficients [1][2][3][4]. This approach is justified in the case of a small contrast of the interference pattern. Since experimental works often involve systems with deep modulation of light intensity, in which there are large local changes of electric field intensity, it is worth examining what the influence of the field dependence of carrier trapping coefficients is. In this work, we present numerical studies of the impact of this relation on the process of space-charge field formation under the stationary interference pattern.The photorefraction phenomenon in semi-insulating materials can be described with the band transport model PDDT (photogeneration -diffusion -drift -trapping) [2]. In descriptions of semiconductor structures the occurrence of one level of deep traps and one level of shallow dopants in the energy gap is usually assumed.Here we scrutinize the material in which shallow dopants are acceptors with concentration , whereas donors with concentration play the role of deep trapping levels. The relationship between the concentrations of donors and acceptors is described by the compensation coefficient . In addition, we assume the total ionization of shallow acceptors, i.e.. They do not take part in photorefractive transitions, but have an important impact on the initial concentration of ionized donors. Ionized donors with the concentration act as trap centers for electrons, while non-ionized donors with the concentration...

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“…where , define the electron mobility in the central and side valleys, while is a distribution function expressing relative occupation of the central valley [7].…”

Section: West Pomeranian University Of Technology In Szczecin Piastómentioning

confidence: 99%

The impact of electron and hole trapping coefficient on nonlinear phenomena in photorefractive multiple quantum well structures

Jabłoński

Ziółkowski

Branecka

et al. 2016

Photon. Lett. Poland

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“…11,12 The main focus of this work is to numerically study the optical nonlinear pulse propagation in an MQW waveguide made of doped Al x Ga 1Àx As, where x is the doping fraction, this type of structure can be used to fabricate photodetector since they exhibit high sensitivity and short time esponse. 6,8 We show that this type of structure has great potential as a (SC) source, which can be integrated to a photonic circuit because of its small size. We study an MQW structure composed of 40 layers, each measuring 30 nm in width for a total of 1.2 m. We focus on wavelength dependent refractive index variations, valid for wavelengths over 1.1 m alike.…”

Section: Introductionmentioning

confidence: 97%

Effects of geometry and doping level on dispersion and spectrum in GaAs/AlGaAs quantum well waveguide for the near-IR region

Herrera

Ocampo

2017

J. Nonlinear Optic. Phys. Mat.

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In this work, we study numerically the optical nonlinear pulse propagation in a multiple quantum well waveguide made of Al x Ga 1Àx As. We show that this type of structure can have great potential as a supercontinuum (SC) source which could be integrated to a photonic circuit, due to its small size. We show that manipulating the geometry and the Al mole fraction x of the structure, the dispersion and nonlinear coe±cient parameters can be controlled.

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Impact of donor compensation ratio on photorefractive two–wave mixing dynamics in multiple quantum wells structures

Cited by 2 publications

References 12 publications

The impact of electron and hole trapping coefficient on nonlinear phenomena in photorefractive multiple quantum well structures

The impact of electron and hole trapping coefficient on nonlinear phenomena in photorefractive multiple quantum well structures

Effects of geometry and doping level on dispersion and spectrum in GaAs/AlGaAs quantum well waveguide for the near-IR region

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