The binding energy and the corresponding wave function of excitons in GaAs-based finite square quantum wells (QWs) are calculated by direct numerical solution three-dimensional Schrödinger equation. precise results for lowest exciton state obtained Hamiltonian discretization using high-order finite-difference scheme. microscopic calculations compared with standard variational approach. energies found two methods coincide within 0.1 meV wide range QW widths. radiative decay rate is QWs...

Photoluminescence and reflectivity spectra of a high-quality InGaAs/GaAs quantum well structure reveal series ultranarrow peaks attributed to the confined exciton states. The intensity these decreases as function temperature, while linewidths demonstrate complex peculiar behavior. At low pumping widths all remain quite narrow $(<0.1\phantom{\rule{0.28em}{0ex}}\mathrm{meV})$ in whole temperature range studied, 4--30 K. stronger pumping, linewidth first increases then drops down with rise....

Abstract Rapid development of spin noise spectroscopy the last decade has led to a number remarkable achievements in fields both magnetic resonance and optical spectroscopy. In this report, we demonstrate new – magnetometric potential use it study acting upon electron spin-system an n -GaAs layer high-Q microcavity probed by elliptically polarized light. Along with external field, applied sample, spectrum revealed Overhauser field created optically oriented nuclei additional, previously...

We report a remarkable enhancement of the magnetic moments excitons as result their motion. This surprising result, which we have observed in magneto-optical studies three distinct zinc-blende semiconductors, GaAs, CdTe, and ZnSe, becomes significant kinetic energy exciton comparable with its Rydberg is attributed to motionally induced changes internal structure exciton. The moment function translational wave vector can be represented by universal equation.

Optical spectroscopy of resonant reflection has been used for both experimental and theoretical studies the exciton-light interaction in wide, high-quality quantum-well structures with widths exceeding exciton Bohr radius by an order magnitude or more. The light mixes low-lying confined states which are captured generalized model developed M. Voronov et al. [Phys. Solid State 49, 1792 (2007)]. We demonstrate that high-energy wide QWs can still be described standard amplitude coefficient from...

We report on the experimental evidence for a nanosecond timescale spin memory based nonradiative excitons with large in-plane wave vector. The effect manifests itself in magnetic-field-induced oscillations of energy optically active (radiative) excitons. detected by spectrally resolved pump-probe technique applied to GaAs/AlGaAs quantum well structure transverse magnetic field persist over timescale, which is orders magnitude longer than characteristic decoherence time system. attributed...

Zeeman splitting of quantum-confined states excitons in InGaAs quantum wells (QWs) is experimentally found to depend strongly on quantization energy. Moreover, it changes sign when the energy increases with a decrease QW width. In 87-nm QW, change observed for excited states, which are above ground state only by few meV. A two-step approach numerical solution two-particle Schr\"odinger equation, taking into account Coulomb interaction and valence-band coupling, used theoretical justification...

The dynamics of electron-spin coherence in $\mathrm{GaAs}∕{\mathrm{Al}}_{0.34}{\mathrm{Ga}}_{0.66}\mathrm{As}$ quantum wells has been studied experimentally by a pump-probe Kerr rotation technique. dephasing time was measured to be $10\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ for 17-nm well containing about ${10}^{10}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$ background electrons at temperature $1.8\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Decrease the electron density causes...

We propose a method of spatial modulation inhomogeneous broadening quantum-well excitonic resonance based on local generation defects produced by focused ion beam. The is applied to fabrication diffraction grating in single InGaAs/GaAs structure irradiating the sample with beam 35-keV He+ ions exposure doses <1012 cm-2. spectrum resonant such narrower than that reflectivity and decreases much faster increasing temperature. A proposed model formation diffractive response scattering...

We present an experimental and theoretical study of the lowest exciton states in a 30-nm single GaAs quantum-well heterostructure different electric fields. found that excitons quantum wells are highly sensitive to field demonstrate nonlinear behavior terms their energy position, amplitude, spectral width, phase resonances reflection spectra. Comparison results with calculations allowed us reliably determine strength layer.

The effect of irradiation by 30‐keV Ga + and 35‐keV He ions (in relatively small doses) on the excitonic reflectivity spectra single InGaAs/GaAs quantum‐well structures is studied. It found that results in decreasing intensity broadening resonances for all doses. shown these changes are not related to a decrease exciton transition oscillator strength and, therefore, irradiation‐induced destruction states, but can be rather ascribed common cause, namely, inhomogeneous proportional exposure...

Multiple frequency quantum beats of a system the coherently excited confined exciton states in high-quality semiconductor structure containing wide InGaAs/GaAs well are experimentally detected by spectrally resolved pump-probe method. The beat signal is observed both at positive and negative delays between pump probe pulses. Several (QB) frequencies experiments, which coincide with interlevel spacings system. A theoretical model developed, allows one to attribute QBs delay four-wave mixing...

In this work we have investigated the exciton reflectance spectra of a high quality heterostructure with GaAs/AlGaAs quantum well in transverse magnetic field (Voigt geometry). It has been shown that application leads to decrease energy distance between spectral features related excitonlike polariton modes. This effect treated as magneto-induced increase mass. We hydrogenlike and diamagnetic models are insufficient describe behavior intermediate fields studied. Considering symmetry problem,...

Picosecond kinetics of polarized resonant photoluminescence (PL) HH excitons in the GaAs/AlGaAs superlattices is studied an external magnetic field. The measurements were made real time using a streak camera. For field aligned along heterostructure growth direction, PL exhibits oscillations degree linear polarization. are ascribed to quantum beats between sublevels optically active excitonic doublet split by plane layers, found exhibit circular These related states and inactive doublets....

The effect of external electric bias on the kinetics circularly polarized photoluminescence (PL) GaAs quantum wells (QWs) is studied experimentally. It found that a negative applied to top surface samples causes appearance slow component in decay PL circular polarization. amplitude this grows with ${U}_{\mathrm{bias}}$ and reaches nearly 100% at ${U}_{\mathrm{bias}}=\ensuremath{-}2\mathrm{V}.$ In transverse magnetic field, polarization shows oscillations related spin precession. changes...

We report on the observation of a significant increase radiative decay rates for exciton transitions in wide (In,Ga)As/GaAs quantum well ($L=95$ nm) magnetic fields up to 6 T applied along growth axis heterostructure. The absolute values are obtained from quantitative analysis resonant features experimentally measured reflectance spectra range optical quantum-confined states. High crystalline quality heterostructure allows us observe ground and several excited with nonradiative broadening...

Optically inactive or dark excitons play an important role in exciton and polariton devices. On one hand, they supply to the light cone feed photoluminescence signal. other repel radiatively active due exchange interaction contribute formation of lateral potentials for condensates. top this, scattering energy relaxation dynamics quasiparticles semiconductors. So far, because optical inaccessibility, studies were focused typically on experimental technique, giving information about quantity...

We report on a method of creating spectrally selective diffractive optical elements based resonantly reflecting mirrors made semiconductor structures with 2D Wannier–Mott excitons. This employs strong dependence resonant reflection coefficient the inhomogeneous broadening determined by exciton scattering quantum‐well structural defects. Realization proposed addressable control excitonic resonance width includes two stages. At first stage substrate surface is exposed to an ion beam intensity...

The robustness of AlGaAs/GaAs quantum well to strong resonant excitation is studied. It was found that lowering Al concentration in barriers 3% does not influence the measured radiative linewidth exciton resonance sample at low intensities. At same time parasitic broadening by an additional illumination strongly suppressed as compared with 30% barriers.

We discuss the implications of a small indium content (3%) in GaAs epilayer on electron and nuclear spin relaxation due to enhanced quadrupolar effects induced by strain. Using weakly perturbative noise spectroscopy, we study dynamics without explicit excitation. The observed temperature dependence indicates presence localized states, which have an increased interaction with surrounding spins. Time-resolved spectroscopy is then applied optically pumped system. It shows multi-exponential...