Study of impurity position effect in pyramid and cone like quantum dots

Khordad, R.; Bahramiyan, H.

doi:10.1051/epjap/2014140080

Cited by 36 publications

(17 citation statements)

References 52 publications

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“…A strong dependence of light absorption on geometry has been demonstrated, for some time, via comparisons between conical and cylindrical nanowire properties [30]. The optical and electronic properties of tapered QDs, including the effects of electric and magnetic fields and donor impurities, have also been studied in different works [31,32].…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…Based on the finite-element method and the Arnoldi algorithm, Avazzadeh et al [39] studied the diamagnetic susceptibility of an off-center hydrogenic donor impurity confined in pyramid and cone-like quantum dots. Effect of impurity position on the electronic structure, hydrogenic impurity binding energy and third harmonic generation of a pyramid and a cone like quantum dot was investigated by Khordad and Bahramian [40]. Also, Lozovski and Piatnytsia [41] analytically obtained energy eigenfunctions and eigenvalues of pyramid-like and cone-like QDs located on the semiconductor surface.…”

Section: Introductionmentioning

confidence: 99%

Finite difference time domain simulation of arbitrary shapes quantum dots

et al. 2019

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Utilizing the finite difference time domain (FDTD) method, energy eigenvalues of spherical, cylindrical, pyramidal and cone-like quantum dots are calculated. To do this, by the imaginary time transformation, we transform the schrödinger equation into a diffusion equation. Then, the FDTD algorithm is hired to solve this equation. We calculate four lowest energy eigenvalues of these QDs and then compared the simulation results with analytical ones. Our results clearly show that simulation results are in very good agreement with analytical results. Therefore, we can use the FDTD method to find accurate results for the Schrödinger equation.

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“…After Bastard's pioneering work on a donor impurity in a semiconductor quantum well [22], many studies have been performed on impurity states in nanostructures [23][24][25][26]; For instance, Al-Hayek and Sandouqa investigated the energy and binding energy of a donor impurity in a quantum dot with Gaussian confinement [27]. Baghramyan et al [28] studied the effects of hydrostatic pressure, temperature, aluminum concentration, and impurity position on the hydrogen-like donor binding energy in GaAs/Ga 1−x Al x As concentric double quantum rings.…”

Section: Introductionmentioning

confidence: 99%

Energy gap renormalization and diamagnetic susceptibility in quantum wires with different cross-sectional shape

et al. 2016

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In this study, we investigate the effect of the cross-sectional shape on the energy gap renormalization and diamagnetic susceptibility in various quantum wires. To this end, we consider quantum wires with different cross-sectional shapes such as circular, square, hexagonal, and triangular. First, we employ the finite-element method and Arnoldi algorithm to solve the Schrödinger equation. Then, we calculate the energy levels, wavefunctions, binding energy, energy gap renormalization, and diamagnetic susceptibility. Our numerical results show that the binding energy decreases when the cross-sectional area is increased for all the quantum wires. Moreover, it is inferred that the cross-sectional shape is not important for large crosssectional area when calculating the binding energy. Indeed, the main parameter is the cross-sectional area rather than the length of a side. The energy gap renormalization decreases with increasing cross-sectional area, regardless of the impurity concentration. We observe that the highest and lowest energy gap renormalization correspond to triangular and circular quantum wires, respectively. The absolute value of the diamagnetic susceptibility increases with increasing crosssectional area for all the quantum wires investigated.

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Study of impurity position effect in pyramid and cone like quantum dots

Cited by 36 publications

References 52 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

Finite difference time domain simulation of arbitrary shapes quantum dots

Energy gap renormalization and diamagnetic susceptibility in quantum wires with different cross-sectional shape

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