Effect of the image potential on the binding energy of excitons in semiconductor quantum wells

Wendler, L.; Hartwig, Beppo

doi:10.1088/0953-8984/3/49/007

Cited by 16 publications

(9 citation statements)

References 17 publications

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“…We have assumed infinite values for the conduction and valence band offsets and have not considered the effect of the image charges due to dielectric mismatch on the exciton ground-state energy. It is well known that the dielectric mismatch between the confined material and the barrier material has a significant effect on the energy levels of quantum wells 38,39 and quantum wires. 40 Similar effects are also expected in quantum dots.…”

Section: Resultsmentioning

confidence: 99%

Optical properties of confined polaronic excitons in spherical ionic quantum dots

2003

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We report the results of a variational calculation of the energy and the oscillator strength of the exciton ground state in a spherical ionic quantum dot as a function of radius, assuming infinite potential barriers. The strong interaction of the exciton with optical phonons is taken into account by using an effective potential between the electron and the hole as derived by Pollmann and Büttner. The values of the exciton ground-state energies calculated using this effective potential are compared with the results of a recent calculation that treats the exciton interaction with confined and interface phonons independently, and excellent agreement is found. Comparisons with two simpler models of excitons reveal that the high degree of confinement in small quantum dots suppresses polaronic corrections in exciton properties. The reduction of the electron-hole correlation in small quantum dots is observed in the behavior of oscillator strength, which becomes less dependent on the form of the effective interaction as the dot size is reduced. A proper definition of exciton transition energy in ionic materials is pointed out, where self-energy renormalization effects are important. The results of our calculation are presented for quantum dots of some ionic materials such as CdSe, GaN, ZnO, and CuCl.

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Section: Resultsmentioning

confidence: 99%

Optical properties of confined polaronic excitons in spherical ionic quantum dots

2003

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“…It was theoretically predicted in the original papers [11][12][13] that excitonic properties of semiconductor thin films surrounded by a dielectric or vacuum should be much more pronounced than that in a bulk. Later this phenomenon was theoretically investigated in quantum wells, [14][15][16][17][18][19] superlattices, 20,21 QWR's, [8][9][10] and quantum dots. 22 Until recently the study of the dielectric enhancement of excitons in real semiconductor nanostructures was restricted to the case when the dielectric constant mismatch is small ͑of the order of 10%͒, and the effect is rather weak.…”

Section: Introductionmentioning

confidence: 99%

Dielectrically enhanced excitons in semiconductor-insulator quantum wires: Theory and experiment

et al. 2000

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We present both theoretical and experimental investigations of optical properties of excitons in semiconductor-insulator quantum wires. Spectra of linear and nonlinear absorption, photoluminescence and its polarization, photoluminescence excitation, time-resolved photoluminescence of GaAs, CdSe, and InP quantum wires 4-6 nm in diameter, crystallized in dielectric matrix, demonstrate the prominent excitonic behavior. In these structures an essential difference of dielectric constants of constituent materials leads to a considerable enhancement of excitons, the binding energies ranging from 120 meV to 260 meV and exciton transitions being well distinguished in nanowires with sufficient dispersion of diameter even at room temperature. A theoretical approach to calculations of the exciton parameters in a semiconductor-insulator cylindrical quantum wire of finite diameter is developed. This approach accounts for a band-gap renormalization due to the spatial confinement and self-image effect, as well as for a dielectric enhancement of the electron-hole interaction. The calculated exciton transition energies and absorption spectra are consistent with the experimental results.

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“…Solving this equation it is convenient to use the characteristic distance a = A2/me2 (Bohr radius) and the Rydberg energy Ry = e2/2a. We introduce the dimensionless values q 2 = m,ye/2~rnl, thickness 1 = L/a, coordinate p = z/L, and energy From (6) we obtain the equation for u(p, 1) dZ where (7) It is impossible to find the exact solution of (7) due to the analytical complexity of the potential (8). On one hand, the first two singular terms of the potential (at p + 0 and e 4 1) do not permit to build PT on the wave functions of the Hamiltonian of the infinitely high rectangular potential (IHRW) well.…”

Section: Spectrum and Wave Functions Methods Of Perturbation Theory (Pt)mentioning

confidence: 99%

Spectrum of an Electron Localized by Electrostatic Image Forces in Thin Semiconductor Layers

Tkach

Holovatsky

Voіtseкhіvsкa

1994

Physica Status Solidi (b)

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The spectrum of an electron confined in a layer with the dielectric constant ϵ, embedded between two media with larger (ϵ> > ϵ) and smaller (ϵ< < ϵ) values of the dielectric constant is calculated. The dependence of the spectrum on the layer thickness and on the ratio between the dielectric constants of the layer and the media is calculated. It is shown that if the crystal thickness increases, the whole spectrum of electrons shifts into the region of negative energies and becomes quasi‐hydrogenic there.

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Effect of the image potential on the binding energy of excitons in semiconductor quantum wells

Abstract: We report the resulls of variational estimates of the binding energy of excitons in quantum wells along the eEect of the image potential.

Cited by 16 publications

References 17 publications

Optical properties of confined polaronic excitons in spherical ionic quantum dots

Optical properties of confined polaronic excitons in spherical ionic quantum dots

Dielectrically enhanced excitons in semiconductor-insulator quantum wires: Theory and experiment

Spectrum of an Electron Localized by Electrostatic Image Forces in Thin Semiconductor Layers

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