Nonequilibrium Fluctuations of Light and Heavy Hole Gas and Observation of Acoustic Plasma Oscillations Associated with Inter-Valence-Band Photoeffect in p-GaAs

Acoustical plasma oscillations in photoexcited electron-hole plasma induced in GaAs layers embedded with InAs quantum dots

“…Moreover, these spectra reveal an anomalous increase in the absolute intensity of quasielastic light scattering with decreasing temperature. This is also a different pattern from that observed earlier [9][10][11]. We believe that the observed scattering is due to selectively photoexcited charge-density fluctuations of the electron-hole plasma [7,8] induced in the GaAs in the presence of a self-organized ensemble of InAs quantum dots.…”

“…We have demonstrated that this model is suitable for optical study of unique features of many-body interactions in the twocomponent plasma. In the near-infrared quasielastic light scattering spectra of p-GaAs samples we have observed well defined low-frequency acoustical plasma oscillation peaks [9][10][11]. As in the case of a classic gaseous plasma of electrons and ions, the existence of the acoustical plasma oscillations together with the well known optical plasma oscillations in multicomponent semiconductor plasmas has been predicted by Pines [12].…”

“…Both anti-Stokes and Stokes electronic quasielastic light scattering spectra are evident in figures 1 and 2. This scattering from the InAs/GaAs quantum dot system exhibits quite different behaviour in comparison with the process of inelastic light scattering by free-electron gas fluctuations observed in n-InP [9] and free-hole gas fluctuations observed in p-GaAs [10,11]. As seen in figure 2 at 77 K the contribution of the lattice scattering is not dominant.…”

Structural, Optical, and Electrical Properties of Semiconductor Compounds Studied by Means of Inelastic Light Scattering from Phonon, Electron, and Coupled Electron–Phonon Excitations: From Bulk to Nanoscale Structures

“…For the two-component charged h-gas systems together with the complex nature of the optic plasmons with plasma frequency presence of another unusual feature for collective excitations behavior, namely, an ionic sound waves, namely acoustic plasmons in p-type GaAs has been demonstrated. [30][31][32] 3.2 Self-selective multi-zone resonance near infrared electronic light scattering in GaAs/InAs quantum dot structures We introduce a self-selective inelastic electronic light scattering (IELS) using steady state near infrared spectroscopy. In the photoluminescence experiments on ensembles of QDs many of excitonic complexes is observed, leading to inhomogeneously broadened lineshapes.…”

<title>Inelastic inter-valence-band scattering of photoexcited holes in quantum dot structures</title>

“…A first attempt to detect such a mode for e-h plasma has been performed in [13}. More recently the acoustic plasmons were observed in a gas of heavy and light holes [11,14] and in two-dimensional electron gas [15]. The experimental observation of the collective acoustic plasmons in our spectra immediately indicates creation of collisionless plasma in which the characteristic motion of the oppositely charged carriers is mostly ballistic (the probed dimension L << 1, the electron mean free path) .…”