Spectrum and polarization of hot-electron photoluminescence in semiconductors

Zakharchenya, B. P.; Mirlin, D. N.; Perel, V. I.; Reshina, I. I.

doi:10.3367/ufnr.0136.198203d.0459

Cited by 69 publications

(28 citation statements)

References 3 publications

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“…Therefore, the conduction-band photogenerated electron distribution in the Brillouin zone has a maximum along ͑perpendicular to͒ the polarization direction for generation from lh ͑hh͒ band, which is distorted by the mixed term ͑20͒. This sym-metry has already been recognized in one-photon excitation, 39 where a mixture of the light-and heavy-hole bands close to the ⌫ point was considered. In Sec.…”

Section: Induced Current Densitymentioning

confidence: 82%

Quantum kinetic theory of two-beam current injection in bulk semiconductors

Sipe¹

2000

Phys. Rev. B

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We develop a theory of current injection in bulk semiconductors by simultaneous excitation with two laser beams with frequencies 2 0 , 0. Coherent mixing of the resulting one-and two-photon transitions generates an effective field A e f f (k) with different strengths at Ϯk points in momentum space. This asymmetry in carrier generation, producing the induced current, is controlled by the relative phase of the two fields. Quantum kinetic equations for the photogenerated carriers are derived from nonequilibrium Green functions. They are simplified here to the Boltzmann limit, and applied to a model of GaAs in the presence of LO phonons. Different forms of the conduction electron distributions result for generation from light-and heavy-hole bands, and give different saturation and relaxation rates for the induced current. Generation of THz radiation by the current is also discussed.

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Section: Induced Current Densitymentioning

confidence: 82%

Quantum kinetic theory of two-beam current injection in bulk semiconductors

Sipe¹

2000

Phys. Rev. B

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“…The recombination rate is evaluated by Fermi's golden rule with the dipole approximation. 42,43 The interband dipole-moment operator is given by d = l,n1,n2 σ=± d l,n1,n2 êl,n1,σ ĥ−l,n2,σ + h.c., (10) where êl,n,σ [ ĥl,n,σ ] is an annihilation operator of an electron [a hole] in the state of ψ e,l,n χ σ [ψ h,l,n χ −σ ] and…”

Section: Photoluminescencementioning

confidence: 99%

Optical Aharonov-Bohm effect on Wigner molecules in type-II semiconductor quantum dots

2011

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We theoretically examine the magnetoluminescence from a trion and a biexciton in a type-II semiconductor quantum dot, in which holes are confined inside the quantum dot and electrons are in a ring-shaped region surrounding the quantum dot. First, we show that two electrons in the trion and biexciton are strongly correlated to each other, forming a Wigner molecule: Since the relative motion of electrons is frozen, they behave as a composite particle whose mass and charge are twice those of a single electron. As a result, the energy of the trion and biexciton oscillates as a function of magnetic field with half the period of the single-electron Aharonov-Bohm oscillation. Next, we evaluate the photoluminescence. Both the peak position and peak height change discontinuously at the transition of the many-body ground state, implying a possible observation of the Wigner molecule by the optical experiment.

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“…Figure 2 illustrates these selection rules for ប E g ͑i.e., for k v Ϸ 0͒; these selection rules, or at least the relative transition rates, are relaxed somewhat when ប approaches the spin-orbit split-off energy gap. 8,9 For a zinc-blende semiconductor which has been optically excited to produce a density N ↑ of spin-up electrons and density N ↓ of spin-down electrons with N = N ↑ + N ↓ , as a measure of the electron spin polarization we define ⌬N = N ↓ − N / 2. From the above selection rules for circularly polarized light, the polarization ͑ ± ͒ dependent absorption coefficient can be arrived at from a simple modification of Eq.…”

Section: ͑1͒mentioning

confidence: 99%

“…It has been known for nearly four decades that the optical excitation of direct band-gap zinc-blende and other semiconductors with above band-gap circularly polarized light creates spin-polarized electrons in the conduction band. 8,9 From measurements of the differential transmission using pumpprobe techniques with the same and oppositely circularly polarized pulses, or from photoluminescence 10 measurements, it is possible to establish the degree of carrier spin polarization and its decay time. 8,[11][12][13][14] Since the hole spin polarization in bulk semiconductors is known to relax 15 in 100 fs, on a longer time scale one typically measures only the electron spin polarization and its evolution.…”

Section: Introductionmentioning

confidence: 99%

Spin-dependent electron many-body effects in GaAs

et al. 2005

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Time-and polarization-resolved differential transmission measurements employing same and oppositely circularly polarized 150 fs optical pulses are used to investigate spin characteristics of conduction band electrons in bulk GaAs at 295 K. Electrons and holes with densities in the 2 ϫ 10 16 cm −3-10 18 cm −3 range are generated and probed with pulses whose center wavelength is between 865 and 775 nm. The transmissivity results can be explained in terms of the spin sensitivity of both phase-space filling and many-body effects ͑band-gap renormalization and screening of the Coulomb enhancement factor͒. For excitation and probing at 865 nm, just above the band-gap edge, the transmissivity changes mainly reflect spin-dependent phase-space filling which is dominated by the electron Fermi factors. However, for 775 nm probing, the influence of many-body effects on the induced transmission change are comparable with those from reduced phase space filling, exposing the spin dependence of the many-body effects. If one does not take account of these spindependent effects one can misinterpret both the magnitude and time evolution of the electron spin polarization. For suitable measurements we find that the electron spin relaxation time is 130 ps.

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Spectrum and polarization of hot-electron photoluminescence in semiconductors

Cited by 69 publications

References 3 publications

Quantum kinetic theory of two-beam current injection in bulk semiconductors

Quantum kinetic theory of two-beam current injection in bulk semiconductors

Optical Aharonov-Bohm effect on Wigner molecules in type-II semiconductor quantum dots

Spin-dependent electron many-body effects in GaAs

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