Optical Absorption and Electroabsorption Related to Electronic and Single Dopant Transitions in Holey Elliptical GaAs Quantum Dots

Vinasco, J.A.; Londoño, Mauricio A.; Restrepo, R.L.; Feddi, E.; Radu, A.; Kasapoğlu, E.; Morales, A. L.; Duque, C.A.

doi:10.1002/pssb.201700470

Cited by 13 publications

(6 citation statements)

References 55 publications

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“…The study is focused on electron confinement effects related to QD dimensions and on the influence of externally applied electric and magnetic fields, with and without on-center donor impurity effects. The Equation ( 4 ), is solved via the FEM [ 34 , 35 , 36 ], using the COMSOL-Multiphysics licensed software [ 37 , 38 , 39 ], with which it is possible to obtain the wave functions and the energies of the different states. The settings used to build an extra fine, user-controlled mesh are: 6185 mesh vertices, 12,104 triangles, 460 edge elements, 10 vertex elements, 0.6179 minimum element quality, 0.8964 medium element quality, 0.2051 element area ratio, and 226.2 nm

mesh area.…”

Section: Theoretical Modelmentioning

confidence: 99%

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

et al. 2023

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A theoretical analysis of optical properties in a ZnS/CdS/ZnS core/shell/shell spherical quantum dot was carried out within the effective mass approximation. The corresponding Schrödinger equation was solved using the finite element method via the 2D axis-symmetric module of COMSOL-Multiphysics software. Calculations included variations of internal dot radius, the application of electric and magnetic fields (both oriented along z-direction), as well as the presence of on-center donor impurity. Reported optical properties are the absorption and relative refractive index change coefficients. These quantities are related to transitions between the ground and first excited states, with linearly polarized incident radiation along the z-axis. It is found that transition energy decreases with the growth of internal radius, thus causing the red-shift of resonant peaks. The same happens when the external magnetic field increases. When the strength of applied electric field is increased, the opposite effect is observed, since there is a blue-shift of resonances. However, dipole matrix moments decrease drastically with the increase of the electric field, leading to a reduction in amplitude of optical responses. At the moment impurity effects are activated, a decrease in the value of the energies is noted, significantly affecting the ground state, which is more evident for small internal radius. This is reflected in an increase in transition energies.

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mesh area.…”

Section: Theoretical Modelmentioning

confidence: 99%

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

et al. 2023

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“…Ref. [28] provides a detailed explanation of the procedure. This approach leaves the problem to solve in the form of a 2D effective differential equation, which needs to be solved to determine the eigenenergies and eigenfunctions of the corresponding effective-mass problem.…”

Section: Theoretical Modelmentioning

confidence: 99%

Elliptical Quantum Rings with Variable Heights and under Spin–Orbit Interactions

Mora-Ramos,

Vinasco,

Radu

et al. 2023

Condensed Matter

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We investigate the electronic properties of a semiconductor quantum ring with an elliptical shape and non-uniform height, allowing for distributed quantum-dot-like bulges along its perimeter. The adiabatic approximation and the finite element method are combined to calculate the allowed electron states in the structure under the effective mass approximation, considering the contributions from Rashba and Dresselahaus spin–orbit interactions and the Zeeman effect in the presence of an applied magnetic field. We discuss the features of the calculated spectra for two different ring geometries: a symmetric one with four dot-like bulges, and an asymmetric one with three hilled protuberances. The information about those states allows us to evaluate the linear optical absorption response associated with interlevel transitions between the ground and lowest excited states. This phenomenon takes place at resonant energies of only a few milielectronvolts. It is observed that spin–orbit interactions tend to quench this response under zero-field conditions in the case of symmetric confinement.

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“…To include the study of the inter-level optical absorption response we calculate the respective coefficients using the following expression [30,31,32]:…”

Section: Theoretical Frameworkmentioning

confidence: 99%

Donor impurity energy and optical absorption in spherical sector quantum dots

Aouami

Feddi

Radu

et al. 2020

Heliyon

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The properties of the conduction band energy states of an electron interacting with a donor impurity center in spherical sector-shaped GaAs-Al 0.3 Ga 0.7 As quantum dots are theoretically investigated. The study is performed within the framework of the effective mass approximation through the numerical solution of the 3D Schrödinger equation for the envelope function via the finite element method. The modifications undergone by the spectrum due to the changes in the conical structure geometry (radius and apical angle) as well as in the position of the donor atom are discussed. With the information regarding electron states the linear optical absorption coefficient associated with transition between confined energy levels is evaluated and its features are discussed. The comparison of results obtained within the considered model with available experimental data in GaAs truncatedwhisker-like quantum dots shows very good agreement. Besides, our simulation leads to identify the lowest energy photoluminescence peak as donor-related, instead of being associated to acceptor atoms, as claimed after experimental measurement (Hiruma et al. (1995) [14]). Also, a checking of our numerical approach is performed by comparing with analytical solutions to the problem of a spherical cone-shaped GaN with infinite confinement and donor impurity located at the cone apex. Coincidence is found to be remarkable.

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Optical Absorption and Electroabsorption Related to Electronic and Single Dopant Transitions in Holey Elliptical GaAs Quantum Dots

Cited by 13 publications

References 55 publications

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

Optical Properties in a ZnS/CdS/ZnS Core/Shell/Shell Spherical Quantum Dot: Electric and Magnetic Field and Donor Impurity Effects

Elliptical Quantum Rings with Variable Heights and under Spin–Orbit Interactions

Donor impurity energy and optical absorption in spherical sector quantum dots

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