Strong Fermi-edge singularity in ultra-high-quality AlGaAs/GaAs quantum wires (original) (raw)
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Physical Review B
Fundamentally different behavior of the Fermi-edge singularity ͑FES͒ in photoluminescence of heavily doped pseudomorphic modulation-doped Al x Ga 1Ϫx As/In y Ga 1Ϫy As/GaAs heterostructures is observed. The noteworthy features are: ͑i͒ the FES enhancement from E F of nϭ1 electronic subband is observed under condition of the nϭ2 subband population, ͑ii͒ the heavy-hole localization energy is directly observed in the FES development, ͑iii͒ the magnitude of the FES increases with increasing temperature at low temperatures, and ͑iv͒ the FES is a nonmonotonic function of the excitation density. A qualitative analysis is performed in terms of heavy-hole localization by potential fluctuations in the In y Ga 1Ϫy As quantum well.
Fermi-Edge Singularity in Luminescence Spectra of P-Type Modulation Doped AlGaAs/GaAs Quantum Wells
Acta Physica Polonica A, 1998
We have studied an enhancement of the oscillator strength for optical transitions near the Fermi energy in p-type modulation-doped quantum wells, which, so far, deserved much less attention than analogous n-type systems, because of the complicated valence band structure involved. The relatively wide (L = 150 Å) quantum wells and high doping levels were used, containing more than one occupied subband. The enhancement in the photoluminescence intensity at the Fermi energy resulted from the strong correlation and multiple scattering of holes near the Fermi edge by the localized electrons. .
Valence-subband structures of GaAs/AlxGa1-xAs quantum wires: The effect of split-off bands
Physical review. B, Condensed matter, 1989
The valence-subband dispersion for GaAs quantum wires in Al, Ga& "As host material is calculated in a coupled-band effective-mass model in which the split-off bands are included. We derive the symmetry-adapted basis functions valid at all k for quantum wires of square and rectangular cross sections. Coupling to the split-off bands is seen to leave the uppermost valence subband largely unaffected near the zone center while the other subbands are more markedly affected. This is in contrast to the case of quantum wells where only the light-hole subbands are coupled to the split-off subbands at the zone center.
High spatial resolution spectroscopy of a single V-shaped quantum wire
Applied Physics Letters, 1997
We report on microscopic photoluminescence of a single V-shaped AlGaAs/GaAs quantum wire. The experiments are performed at low temperature by selectively exciting 1 m 2 of the sample. The main photoluminescence line is split into sharp peaks of width less than 0.5 meV and separated by a few meV. The energy position and the intensity of the peaks are characteristic of the scanned quantum wire. First microphotoluminescence results suggest that localization phenomena are predominant in the quantum wire. They are due to the formation of extended monolayer-step islands, larger than the exciton radius, as in the case of high-quality quantum wells. © 1997 American Institute of Physics. ͓S0003-6951͑97͒00343-4͔
Physical Review Letters, 1996
The linear and nonlinear optical properties of realistic quantum wires are studied through a theoretical approach based on a set of generalized semiconductor Bloch equations. Our scheme allows a full threedimensional multisubband description of electron-hole correlation for any confinement profile, thus permitting a direct comparison with experiments for available quantum-wire structures. Our results show that electron-hole Coulomb correlation removes the one-dimensional band-edge singularities from the absorption spectra, whose shape is heavily modified with respect to the ideal free-carrier singlesubband case over the whole density range. [S0031-9007(96)00125-1]
Photo- and cathodoluminescence of AlGaAs single quantum wires on vicinal GaAs (110) surfaces
Solid-State Electronics, 1996
AlGaAs quantum wires are naturally formed by the compositional modulation in an AlGaAs layer on vicinal GaAs (110) surfaces with quasi-periodic giant growth steps by molecular beam epitaxy. We put an Al mask with a 0.3pm wide slit on the sample surface to get the single quantum wire's photoluminescence (PL). Two sharp PL bands are observed through this slit and are concluded to come from the two single quantum wires. Cathodoluminescence (CL) spot spectra with a small excitation area show the fine structures with several sharp lines which originate from different quantum wires. The monochromatic CL images clearly show the individual single quantum wires.