Off‐center shallow donors in a spherical Si quantum dot with dielectric border

Cristea, M.; Niculescu, E.C.

doi:10.1002/qua.23179

Cited by 8 publications

(2 citation statements)

References 38 publications

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“…This can be due to the quantum confinement inside the core. But outside the core the wavefunction becomes more spread out [51] increasing the dipole matrix elements.…”

Section: Nanostructure Core-shell With Off-center Hydrogenic Impuritymentioning

confidence: 99%

Effects of the magnetic field and the off-center displacement on the third-order nonlinear optical susceptibility of inverted core/shell spherical one-electron quantum dots

Negoukoumé Abdoulaï,

Melingui Melono,

Motapon

2023

Phys. Scr.

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The third order nonlinear optical susceptibility (TONOS) of an inverted ZnS/CdSe core–shell spherical quantum dot embedded in SiO 2-matrix with or without impurity, and subjected to an external magnetic field is investigated. Within the framework of effective mass approximation and using B-splines basis functions, the energy levels, the dipole matrix elements and the TONOS are computed. The dielectric mismatch in the interface dots as well as the effective mass dependence on the core and shell regions are taken into account. It is revealed that, simultaneously the shell size, magnetic field and off-center displacement have a noticeable effect on the positions and the heights of the peaks of the TONOS. Moreover, we have shown that, due to the magnetic field and the off-center displacement effects, the TONOS takes different profiles associated with the polarization direction (parallel and perpendicular). In the perpendicular polarization, two peaks of the nonlinear optical properties appear for each off-center displacement value corresponding to the two transversal allowed transitions. The shift towards higher energies of the peak position and the reduction of the intensity of the peak when the magnetic field increases are recorded in the transversal transition case. Furthermore, in the longitudinal transition, as increasing the magnetic field strength, the intensity of the peak of the TONOS grows and the position of the peak is shifted towards lower frequencies. The dielectric constant, effective mass and conduction band offset of the materials that constitute the core and shell are equally found to modify significantly the main features of the susceptibility.

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“…This can be due to the quantum confinement inside the core. But outside the core the wavefunction becomes more spread out [51] increasing the dipole matrix elements.…”

Section: Nanostructure Core-shell With Off-center Hydrogenic Impuritymentioning

confidence: 99%

Effects of the magnetic field and the off-center displacement on the third-order nonlinear optical susceptibility of inverted core/shell spherical one-electron quantum dots

Negoukoumé Abdoulaï,

Melingui Melono,

Motapon

2023

Phys. Scr.

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“…Among the pioneers who have examined this case, Allan et al (1995) [35] have studied the hydrogenic impurity levels, dielectric constant, and Coulomb charging effects in silicon crystallites. Afterwards, Cristea and Niculescu [36] have reported the electronic properties of a spherical Si QD with dielectric border, considering the dielectric mismatch at the core/shell interface, using a finite element method with triangular element and variable steps. Such kinds of systems with various material types such as inverted and non inverted CdSe/ZnS [37], type-I PbSe/CdSe CSQD [38] and recently, inverted and non inverted CdSe/ZnTe [39], have been subject of numerous studies taking into consideration various types of external constraints.…”

Section: Introductionmentioning

confidence: 99%

Binding energies, oscillator strengths of core/shell spherical quantum dots with or without on- or off-center donor impurities under an external magnetic field

Aboulaï¹,

Melono²,

Doba³

et al. 2022

Phys. Scr.

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Non-relativistic energy levels, binding energies and oscillator strengths of CdSe⁄ZnT e core/shell spherical quantum dots with or without impurities submitted to an external magnetic ﬁeld have been investigated by using a B-spline based variational method, within the framework of the eﬀective mass approximation. In the case where the system contains hydrogenic impurity, the eﬀects of its oﬀ-center displacement combined to the height of the conﬁning potential have also been studied. The dielectric constant as well as the eﬀective mass are considered to be dependent on the radius. The modiﬁcations occurring due to the presence of the magnetic ﬁeld have been analyzed. We have found that the electronic and optical properties are strongly aﬀected by the magnetic ﬁeld strength, the spatial conﬁnement and the oﬀ-center displacement. The oscillator strengths and the binding energies increase with the magnetic ﬁeld, but its eﬀect on the binding energies (both ground and excited states) is dimmed by the reduction of the core-to-shell radii ratio and the increase of the oﬀ-center displacement to the vicinity of the shell. However, the oscillator strengths increase with the magnetic ﬁeld when the oﬀ-center displacement increases towards the shell.

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Impurity states and photoionization cross section in CdSe/ZnS core–shell nanodots with dielectric confinement

Niculescu

Cristea

2013

Journal of Luminescence

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Off‐center shallow donors in a spherical Si quantum dot with dielectric border

Cited by 8 publications

References 38 publications

Effects of the magnetic field and the off-center displacement on the third-order nonlinear optical susceptibility of inverted core/shell spherical one-electron quantum dots

Effects of the magnetic field and the off-center displacement on the third-order nonlinear optical susceptibility of inverted core/shell spherical one-electron quantum dots

Binding energies, oscillator strengths of core/shell spherical quantum dots with or without on- or off-center donor impurities under an external magnetic field

Impurity states and photoionization cross section in CdSe/ZnS core–shell nanodots with dielectric confinement

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