Hydrostatic pressure effects on the donor impurity‐related photoionization cross‐section in cylindrical‐shaped GaAs/GaAlAs quantum well wires

Correa, J.D.; Cepeda-Giraldo, O.; Porras‐Montenegro, N.; Duque, C.A.

doi:10.1002/pssb.200405225

Cited by 22 publications

(4 citation statements)

References 14 publications

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“…These studies have considered the donor and acceptor impurity binding energies and density of impurity states (DOIS) in various geometries of the above-mentioned nanostructures. The hydrostatic pressure, uniaxial stress, and electric field effects, in the low temperature regime (close to 4 K), have been reported for donor impurities in single QWs [10][11][12], symmetrical and asymmetrical double quantum wells (DQW) [13,14], QWWs [15,16] and GaAs QDs [17][18][19]. As a general feature, the studies show that the binding energy of a donor electron is enhanced by increasing the hydrostatic pressure and the uniaxial stress.…”

Section: Introductionmentioning

confidence: 87%

A theoretical study of the effects of uniaxial stress and spatial dielectric functions on the density of states of shallow donor impurities in a GaAs quantum well dot of circular geometry

Oketch,

Hannington Odhiambo Oyoko

2024

Rev. Mex. Fís.

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In the present work, we have carried out a comparative study of the effects of uniaxial stress and spatial dielectric functions on the density of impurity states (DOIS) of shallow donor impurities in a GaAs quantum well dot of circular cross-section. Using a trial wave function in the effective mass approximation, we carried out calculations for a range of binding energies of hydrogenic (dielectric constant) and non-hydrogenic (spatial dielectric functions) donors for various applied uniaxial stress and for different uniaxial lengths of the quantum dot. Our results show that, for a constant axial length of the quantum dot and constant uniaxial stress, the DOIS for the donor impurity is markedly enhanced for the non-hydrogenic donor impurity over that for purely hydrogenic donor impurity. At constant axial length, the applied uniaxial stress enhances the DOIS in both cases. The density of impurity states has also been studied for a constant applied uniaxial stress for different axial lengths of the quantum dot. Here, again, the DOIS increases with increasing axial length of the quantum dot. In fact, the enhanced DOIS is observed throughout the range of binding energies considered. These results show that not only does the DOIS vary with the applied uniaxial stress and spatial dielectric functions they are also different for various axial lengths of the quantum dot. These findings indicate that is important to take into account the effect of applied uniaxial stress and spatial dielectric functions when performing experimental studies of electronic, optical and transport properties of such nanostructures as quantum dots.

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Section: Introductionmentioning

confidence: 87%

A theoretical study of the effects of uniaxial stress and spatial dielectric functions on the density of states of shallow donor impurities in a GaAs quantum well dot of circular geometry

Oketch,

Hannington Odhiambo Oyoko

2024

Rev. Mex. Fís.

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“…The 1s impurity state is taken as ground level for D 0 and the 1p level of one electron system without the impurity is taken as the final state for D 0 as similar with previous studies. 6,[8][9][10][11]14 In order to calculate the numerical values of the photoionization cross-section given by Eq. ( 4), F ef f /F 0 is taken as approximately unity because the calculation of this quantity is very difficult and it has no effect on the photoionization cross-section shape [9][10][11][12] .…”

Section: A Theory Of Photoionization Cross-sectionmentioning

confidence: 99%

“…Although there are no experimental studies, the photoionization cross section of a hydrogenic impurity in low-dimensional quantum structures has been studied theoretically by many authors. [6][7][8][9][10][11][12][13][14] The cross section strongly depends on the impurity binding energy and its wave function. 8 The photoionization cross section is still studied extensively under different physical parameters (i.e electric field, magnetic field, hydrostatic pressure) in low-dimensional quantum nano structures.…”

Section: Introductionmentioning

confidence: 99%

The photoionization cross section of a hydrogenic impurity in a multi-layered spherical quantum dot

Şahin

Tek

Erdinç

2012

Journal of Applied Physics

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TurkeyIn this study, we have investigated the photoionization cross section of an on-center hydrogenic impurity in a multi-layered spherical quantum dot. The electronic energy levels and their wave functions have been determined fully numerically by shooting method. Also, we have calculated the binding energy of the impurity by using these energy values. The photoionization cross section has also been computed as a function of the layer thickness and normalized photon energies. We have discussed in detail the possible physical reasons behind the changes in the binding energies and photoionization cross section. It is observed that both the binding energies and the photoionization cross sections depend strongly on the layer thickness and photon energies.

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“…They found that the cross-section rises steeply at the threshold frequency and then decreases with photon frequency. Variational procedure was used to study the influence of an axial magnetic field and hydrostatic pressure on the binding energy and the impurity related photoionization cross-section in quantum wire [24,25]. The findings revealed that the photoionization crosssection strongly depends on the symmetry of the potential that confines the carriers.…”

Section: Introductionmentioning

confidence: 99%

Variation of the Photoionization Cross-Section with the Position of a Hydrogenic Donor Impurity in a Gallium Arsenide Quantum Well Dot of Square Cross-Section

Otieno¹

2018

AJOP

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In the present work, a theoretical study of the variation of the photoionization cross-section with the incident photon frequency and the axial position of a hydrogenic donor impurity in GaAs quantum well dot of square cross-section is carried out. In the calculation, a trial wave function in the effective mass approximation and a finite potential well is used. The wave function is constructed with an appropriate envelope wave function that satisfies the boundary conditions, i.e., the wave function vanishes at the boundary. A trial wave function is employed to calculate the total energy of the hydrogenic donor impurity in the ground state. The total energy is then minimized with respect to the variational parameter in the trial wave function to obtain the minimum energy. The minimized total energies are then used to determine the donor binding energies within the quantum dot. It is observed that for a quantum dot of constant cross-section, the binding energy increases with a decrease in dot length to a peak value; thereafter it decreases rapidly towards zero. The binding energies obtained are used to compute the photoionization cross-section of the hydrogenic donor impurity as a function of the incident photon frequency for different positions of the donor impurity. It is observed that the photoionization cross-sections rise steeply to their peaks from almost zero value then gradually decrease as the photon frequency increases until they become almost constant for very high photon frequencies. The photoionization cross-section peak is much higher for the hydrogenic donor impurity located closest to the centre of the quantum well dot than for donor impurity located farther away from the dot centre. This indicates that the photoionization cross-section is sensitive to the location of the donor impurity in the quantum dot and to the incident photon frequency.

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Hydrostatic pressure effects on the donor impurity‐related photoionization cross‐section in cylindrical‐shaped GaAs/GaAlAs quantum well wires

Cited by 22 publications

References 14 publications

A theoretical study of the effects of uniaxial stress and spatial dielectric functions on the density of states of shallow donor impurities in a GaAs quantum well dot of circular geometry

A theoretical study of the effects of uniaxial stress and spatial dielectric functions on the density of states of shallow donor impurities in a GaAs quantum well dot of circular geometry

The photoionization cross section of a hydrogenic impurity in a multi-layered spherical quantum dot

Variation of the Photoionization Cross-Section with the Position of a Hydrogenic Donor Impurity in a Gallium Arsenide Quantum Well Dot of Square Cross-Section

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