Exciton states in conical quantum dots under applied electric and magnetic fields

Heyn, Ch.; Radu, A.; Vinasco, J.A.; Laroze, David; Restrepo, R.L.; Tulupenko, V.; Hieu, Nguyen N.; Phuc, Huynh V.; Mora-Ramos, M.E.; Ojeda, J.H.; Morales, A. L.; Duque, C.A.

doi:10.1016/j.optlastec.2021.106953

Cited by 35 publications

(22 citation statements)

References 42 publications

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“…Additionally, comparisons were made with a previous more elaborated model [47], which considers the 8-bands k • p theory and configuration interaction with deviations only by a few percent. In Reference [46], and in this work, the electron-hole Coulomb interaction obtained via a perturbative calculation was corroborated with variational calculations, considering two types of trial functions: (i) a hydrogenic-like function with one variational parameter [48,49]; and (ii) a trial function constructed by the product of two independent Gaussian functions. In this second case, two variational parameters were used to describe the radial problem and the problem along the axial direction [50,51] separately.…”

Section: Theoretical Modelmentioning

confidence: 61%

“…174 eV, and ε = 13 [46,57]. In this subsection, the impurity and static magnetic field effects on GaAs-Al 0.3 Ga 0.7 As truncated conical QD are explored.…”

Section: Resultsmentioning

confidence: 99%

“…We should note that, in this article, we followed the same strategy previously used in conical QDs subjected to combined effects of electric and magnetic fields [46]. In Reference [46], the calculations of the electron and hole states using the FEM were contrasted with results obtained through a diagonalization process, with an orthonormal basis composed of a product between Bessel and sinusoidal functions, with a coincidence of up to 0.1 meV. Additionally, comparisons were made with a previous more elaborated model [47], which considers the 8-bands k • p theory and configuration interaction with deviations only by a few percent.…”

Section: Theoretical Modelmentioning

confidence: 99%

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Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

et al. 2021

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Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (ii) CdSe–CdTe core–shell type-II quantum dot. For the first system, the impurity position and the applied magnetic field direction were chosen to preserve the system’s azimuthal symmetry. The finite element method obtains the solution of the Schrödinger equations for electron or hole with or without impurity with an adaptive discretization of a triangular mesh. The interaction of the electron and hole states is calculated in a first-order perturbative approximation. This study shows that the magnetic field and donor impurities are relevant factors in the optoelectronic properties of conical quantum dots. Additionally, for the CdSe–CdTe quantum dot, where, again, the axial symmetry is preserved, a switch between direct and indirect exciton is possible to be controlled through geometry.

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Section: Theoretical Modelmentioning

confidence: 61%

“…174 eV, and ε = 13 [46,57]. In this subsection, the impurity and static magnetic field effects on GaAs-Al 0.3 Ga 0.7 As truncated conical QD are explored.…”

Section: Resultsmentioning

confidence: 99%

Section: Theoretical Modelmentioning

confidence: 99%

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Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

et al. 2021

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“…The analytical relations of the linear 𝜒 (1) and nonlinear 𝜒 (3) susceptibility are expressed as [40][41][42][43] 𝜀 0 𝜒 (1)…”

Section: Optical Propertiesmentioning

confidence: 99%

High pressure and polaron effects on optical properties of GaN wedge-shaped quantum dot

2022

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In the paper, the optical properties of GaN wedge-shaped quantum dot (WSQD) under influence both pressure and electron-phonon (e-p) interaction have been investigated. To this end, the energy difference and dipole matrix elements are evaluated by considering the effects of e-p and pressure. Then, the refractive index changes (RICs) and absorption coefficients (ACs) are evaluated. It is deduced that the energy difference and dipole matrix elements reduce by considering the e-p and pressure effects. It is resulted that the pressure enhances the e-p effect on the energy difference. The ACs and RICs move to lower energies by considering the ep and pressure effects. The RICs and ACs are raised in the presence of e-p effect whereas they are reduced with considering the pressure. With considering the e-p and pressure effects on total ACs, it is seen that the peak of AC splits into two peaks.

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“…However, during the growth process, the constraints generated by lattice mismatch of different materials and the strain of WL cause non-symmetrical and non-homogenous shapes. Thus, different shapes with different size dispersions can be observed by TEM imaging: hemispherical, disk, cylinder, lens, ring, conical, pyramidal, dome, oblate and prolate or semi oblate and prolate [11][12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Quantum Confined Stark Effect on the Linear and Nonlinear Optical Properties of SiGe/Si Semi Oblate and Prolate Quantum Dots Grown in Si Wetting Layer

et al. 2021

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We have studied the parallel and perpendicular electric field effects on the system of SiGe prolate and oblate quantum dots numerically, taking into account the wetting layer and quantum dot size effects. Using the effective-mass approximation in the two bands model, we computationally calculated the extensive variation of dipole matrix (DM) elements, bandgap and non-linear optical properties, including absorption coefficients, refractive index changes, second harmonic generation and third harmonic generation as a function of the electric field, wetting layer size and the size of the quantum dot. The redshift is observed for the non-linear optical properties with the increasing electric field and an increase in wetting layer thickness. The sensitivity to the electric field toward the shape of the quantum dot is also observed. This study is resourceful for all the researchers as it provides a pragmatic model by considering oblate and prolate shaped quantum dots by explaining the optical and electronic properties precisely, as a consequence of the confined stark shift and wetting layer.

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Exciton states in conical quantum dots under applied electric and magnetic fields

Cited by 35 publications

References 42 publications

Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

High pressure and polaron effects on optical properties of GaN wedge-shaped quantum dot

Quantum Confined Stark Effect on the Linear and Nonlinear Optical Properties of SiGe/Si Semi Oblate and Prolate Quantum Dots Grown in Si Wetting Layer

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