arXiv subjects

Gerard Czajkowski

Publications and source records attributed to Gerard Czajkowski.

24 records · Page 2Linked to original sources

arXiv2016

Magnetooptical Properties of Rydberg Excitons - Center-of-Mass Quantization Approach

We show how to compute the magnetooptical functions (absorption, reflection, and transmission) when Rydberg Exciton-Polaritons appear, including the effect of the coherence between the electron-hole pair and the electromagnetic field, and the polaritonic effect. Using the Real Density Matrix Approach the analytical expressions for magnetooptical functions are obtained and numerical calculations for Cu$_2$0 crystal are performed. The influence of the strength of applied external magnetic field on the resonance displacement of excitonic spectra is discussed. We report a good agreement with recently published experimental data.

cond-mat.mes-hall↗

arXiv2016

Electrooptical Properties of Rydberg Excitons

We show how to compute the electrooptical functions (absorption, reflection, and transmission) when Rydberg Excitons appear, including the effect of the coherence between the electron-hole pair and the electromagnetic field. With the use of Real Density Matrix Approach numerical calculations applied for Cu$_2$0 crystal are performed. We also examine in detail and explain the dependence of the resonance displacement on the state number and applied electric field strength. We report a good agreement with recently published experimental data.

cond-mat.mes-hall↗

arXiv2015

Optical Properties of Rydberg Excitons and Polaritons

We show how to compute the optical functions when Rydberg Excitons appear, including the effect of the coherence between the electron-hole pair and the electromagnetic field. We use the Real Density Matrix Approach (RDMA), which, combined with Green's function method, enables one to derive analytical expressions for the optical functions. Choosing the susceptibility, we performed numerical calculations appropriate to a Cu$_2$0 crystal. The effect of the coherence is displayed in the line shape. We also examine in details and explain the dependence of the oscillator strength and the resonance placement on the state number. We report a good agreement with recently published experimental data.

cond-mat.mes-hall↗

arXiv2015

Quantum Confined Stark Effect in Wide Parabolic Quantum Wells

We show how to compute the optical functions of Wide Parabolic Quantum Wells (WPQWs) exposed to uniform electric F applied in the growth direction, in the excitonic energy region. The effect of the coherence between the electron-hole pair and the electromagnetic field of the propagating wave including the electron-hole screened Coulomb potential is adopted, and the valence band structure is taken into account in the cylindrical approximation. The role of the interaction potential and of the applied electric field, which mix the energy states according to different quantum numbers and create symmetry forbidden transitions, is stressed. We use the Real Density Matrix Approach (RDMA) and an effective e-h potential, which enable to derive analytical expressions for the WPQWs electrooptical functions. Choosing the susceptibility, we performed numerical calculations appropriate to a GaAs/GaAlAs WPQWs. We have obtained a red shift of the absorption maxima (Quantum Confined Stark Effect), asymmetric upon the change of the direction of the applied field (F -> -F), parabolic for the ground state and strongly dependent on the confinement parameters (the QWs sizes), changes in the oscillator strengths, and new peaks related to the states with different parity for electron and hole.

cond-mat.mes-hall↗

arXiv2015

Excitonic Spectra of Wide Parabolic Quantum Wells

The optical properties of wide Quantum Wells are considered, taking into account the screened electron-hole interaction potential and parabolic confinement potentials, different for the electrons and for the holes. The role of the interaction potential which mixes the energy states according to different quantum numbers is stressed. The results obtained by our method are in agreement with the observed spectra and give the possibility to the assessment of the resonances.

cond-mat.mes-hall↗

arXiv2008

Resonant Energy Transfer from Organics to Quantum Dots and Carrier Multiplication

It was shown in the recent experiments that the hybrid organic/inorganic resonant structures can provide a flexible materials platform aimed at the design of novel light emitting devices. The applications of hybrid structures for photovoltaic solar cell can also be useful. We pay attention in this note that the resonant energy transfer in hybrid structure from the organic thin layer to the semiconductor nanostructures can drastically increase the intensity of the free carrier generation. To demonstrate this idea we use the results of recently published paper by Zhang et al., Nature Nanotechnology 2, 555 (2007), demonstrating the highly efficient resonance energy transfer from J-aggregates layer to semiconductor nanocrystals. It is known that the semiconductor nanocrystals with small energy gap represent a promising route to increased solar conversion in single--junction photovoltaic cells. We argue that the using of nanocrystals with small energy gap in the hybrid organic/inorganic structures similar to created by Zhang et al. can increase tens times the total intensity of carrier multiplication. The organic part in such hybrid structures will play a role of the peculiar organic concentrator of the light energy.

cond-mat.mtrl-sci↗