Spectrum and polarization of hot-electron photoluminescence in semiconductors

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

doi:10.1070/pu1982v025n03abeh004519

Cited by 155 publications

(56 citation statements)

References 4 publications

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“…Therefore, the valleys do not determine the anisotropy. On the other hand, an isotropic r R in the 111 plane is consistent with the symmetry of the heavy hole band [90].…”

Section: Polarization Properties Of the Photoluminescence Under Resonmentioning

confidence: 57%

“…The influence of the electronic transitions on the absorption and the emission processes is neglected. This is a good approximation if the excited carriers are able to relax before recombination, but in the absence of relaxation the electronic states and their symmetry are important in determining the polarization [60,90,91]. Below we examine the polarization in porous silicon in the resonant excitation regime.…”

Section: Polarization Properties Of the Photoluminescence Under Resonmentioning

confidence: 97%

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Optical Properties of Si Nanocrystals

Ковалев¹,

Heckler²,

Polisski³

et al. 1999

phys. stat. sol. (b)

455

321

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“…Therefore, the valleys do not determine the anisotropy. On the other hand, an isotropic r R in the 111 plane is consistent with the symmetry of the heavy hole band [90].…”

Section: Polarization Properties Of the Photoluminescence Under Resonmentioning

confidence: 57%

Section: Polarization Properties Of the Photoluminescence Under Resonmentioning

confidence: 97%

Optical Properties of Si Nanocrystals

Ковалев¹,

Heckler²,

Polisski³

et al. 1999

phys. stat. sol. (b)

455

321

View full text Add to dashboard Cite

“…The anisotropy parameter A equals +1 for the transition from the light-hole valence band while \ = -1 for the transition from the heavy-hole band. 7 Because of the larger density of states of the heavy-hole band, the latter transition is the more intense. For it, the right-hand side of Eq.…”

mentioning

confidence: 99%

Femtosecond Orientational Relaxation of Photoexcited Carriers in GaAs

Oudar¹,

et al. 1984

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The anisotropy of optical absorption saturation by intense linearly polarized light pulses is measured with subpicosecond resolution in GaAs at 77 K, at a photon energy slightly above the band gap. For an electron-hole pair density of about 6xl0 17 cm -3 , the momentum orientational relaxation time is determined to be 190 fs, most likely due to carrier-carrier scattering.PACS numbers: 72.20.JvThe development of picosecond, and now femtosecond lasers, has allowed direct studies of the dynamics of hot photoexcited carriers in semiconductors. 1 "" 6 These works have shown that, on a very short time scale (usually less than 1 ps), a quasiequilibrium electron-hole (e-h) plasma is established through the combined action of carriercarrier and carrier-phonon interactions. While the subsequent cooling of this e-h plasma towards the lattice temperature is well documented, 6 little is known about the primary stage of the carrier relaxation. Recently Tang and Erskine 5 have observed in Al x Gai_ x As femtosecond transients due to the energy relaxation of individual Bloch states. On the other hand, linearly polarized light generates carriers with an anisotropic momentum distribution; the observation on a steady-state basis of a polarized photoluminescence 7 is a clear manifestation of the primary stage of carrier relaxation, since the anisotropy of their momentum distribution disappears within a few electronic collisions. Related to this, Smirl et al. observed picosecond transient orientational gratings 3 due to anisotropic state filling in germanium, but could only deduce an upper limit of the relaxation time.We report a direct determination of the orientational relaxation time (in k space) of e-h pairs created by linearly polarized subpicosecond pulses in GaAs at 77 K. The polarized pump pulse increases the sample transmission by filling states near the band edge, with an anisotropic momentum distribution. This anisotropy is measured through probing, by a weaker test pulse, the corresponding anisotropy of optical absorption saturation. Polarization variations are recorded as a function of the relative delay between pump and test pulses; hence this technique is the time-domain counterpart of polarization spectroscopy, 8 well known for its high sensitivity. In the present case, it provides direct information about the randomization of the initially anisotropic distribution of carriers. In order to have the carrier-carrier interactions as the dominant scattering mechanism, we tuned the excitation wavelength at 806 nm, creating e-h pairs with excess energy less than the threshold for optical phonon emission.The connection between our optical measurement and the e -h momentum distributions is as follows. The transition rate between valence and conduction states of wave vector k is proportional to the square of the matrix element P cv (k), projected on to the optical wave polarization e f (/=p or t for pump or test). In the present case of small carrier kinetic energy, isotropic parabolic bands can be assumed. For linear polariza...

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“…The position of this peak is also bias independent, and we attribute this feature to recombination of electrons in the emitter region of the structure with holes in the spin-orbit split off valence band (e-h so recombination). Such recombination has previously been observed in PL spectroscopy by Zakharchenya et al [7]. In the present experiment, the split off valence band in the emitter is populated by high-energy ballistic holes injected through the barrier from the hole accumulation layer on the p-type side of the structure.…”

mentioning

confidence: 71%