Temat: 71.35.-y - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: The Nonlinear Absorption Coefficient for Direct Two-Photon Creation of Biexciton
Autorzy:: Ungier, W.
Suffczyński, M.
Tematy:: 71.35.-y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2030428.pdf Link otwiera się w nowym oknie
Opis:: The absorption coefficient for the two-photon creation of biexciton is calculated for CuCl and wurtzite crystals. Because of the resonance effect only the intermediate lowest optically active excitonic states are taken into account. The absorption coefficient is expressed by a functional of the biexciton envelope. The numerical results are computed with the envelope function of Hylleraas-Ore type (modified and minimized by Brinkman et al). The obtained results for CuCl are in good agreement with absorption measurements published by Gale and Mysyrowicz.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The Radiative Biexciton-exciton Recombination in Wurtzite Crystals
Autorzy:: Ungier, W.
Tematy:: 71.35.-y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1992347.pdf Link otwiera się w nowym oknie
Opis:: In the effective mass approximation in the two-band model of semiconductor the dipole moment matrix element due to the biexciton-exciton transition is expressed by the functional of the exciton and biexciton envelopes. In comparison to previous estimations of the biexciton-exciton transition probability the detailed band structure at band extrema was taken into account and the biexciton envelope optimized by variational calculation was used in calculations. The oscillator strength ratio I$\text{}^{2}$=f$\text{}_{biex-ex}$/f$\text{}_{band-to-band}$ is given for several values of σ=m$\text{}_{e}$/m$\text{}_{h}$. The calculated functional I for CdS is about four times smaller compared to that obtained by Hanamura. The calculated giant oscillator strength of the biexciton-exciton recombination in CdS is f$\text{}_{biex-ex}$=4×10$\text{}^{2}$.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of Semiconductor Bands Bending on Exciton Photoluminescence
Autorzy:: Konin, A.
Tematy:: 71.35.-y
71.35.Cc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1813400.pdf Link otwiera się w nowym oknie
Opis:: A theoretical model for calculation of the Wannier-Mott exciton distribution in semiconductor sample accounting for the energy bands bending near semiconductor surface is presented. It is shown that the exciton distribution essentially depends on the surface potential under certain sample surface and bulk parameters. Changing the surface potential value we can study the exciton photoluminescence from the illuminated surface and from a thin layer near this surface.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: From Localised to Ballistic Excitons in GaAs Quantum Wells
Autorzy:: Pulizzi, F.
Christianen, P. C. M.
Maan, J. C.
Eshlaghi, S.
Reuter, D.
Wieck, A. D.
Tematy:: 71.35.-y
71.36.+c; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2028827.pdf Link otwiera się w nowym oknie
Opis:: The lateral motion of excitons in GaAs quantum wells is studied by means of spatially resolved photoluminescence. We show that at low temperatures (4.2 K) the exciton motion evolves from localised excitons (zero mobility) in thin quantum wells to extremely high mobilities in wide wells. We find that for the widest quantum well investigated the observed motion cannot be explained by simple exciton diffusion and must be explained by the propagation of ballistic exciton polaritons.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Direct Two-Photon Creation of Excitonic Molecule in CuCl
Autorzy:: Ungier, W.
Janiszewski, P.
Suffczyński, M.
Tematy:: 71.35.-y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2014354.pdf Link otwiera się w nowym oknie
Opis:: The probability of direct excitation of excitonic molecule in the two-photon absorption process is calculated with an Hylleraas-Ore type biexciton envelope, which is variationally optimized. In the second order of perturbation, because of the resonance effect, only the exciton Γ$\text{}_{5}$ intermediate state is taken into account. The band structure at band extrema due to spin-orbit interaction is assumed. The transition probability of two-photon absorption is expressed by matrix element between the free exciton and the biexciton envelopes. The obtained probability of two-photon absorption in CuCl is about three orders of magnitude smaller when compared to that obtained by Hanamura.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Optically Detected Magnetic Resonance of Excess Electrons in CdTe/(Cd,Mg)Te Quantum Wells
Autorzy:: Hu, C. Y.
Ossau, W.
Yakovlev, D. R.
König, B.
Wojtowicz, T.
Karczewski, G.
Kossut, J.
Tematy:: 76.70.Hb
71.35.-y
71.35.Ji; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1969094.pdf Link otwiera się w nowym oknie
Opis:: The spin resonance of excess electrons is observed with the detection either on the neutral or the negatively charged exciton X$\text{}^{-}$ emission in type I CdTe/(Cd,Mg)Te quantum wells with excess electrons of low density. It is found that the electron spin-dependent and electron spin-conserving formation and recombination of X$\text{}^{-}$ make the optical detection of the spin resonance of excess electrons feasible. For the first time, optically detected magnetic resonance is used to study fast optical transition processes in the nanosecond timescale where the microwave-induced magnetic transition rate is much lower than the optical transition rate.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Shallow Donors and Acceptors in GaN; Bound Excitons and Pair Spectra
Autorzy:: Stępniewski, R.
Wysmołek, A.
Tematy:: 71.35.-y
71.55.Eq
71.38.+i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1946873.pdf Link otwiera się w nowym oknie
Opis:: Recent photoluminescence results obtained for homoepitaxial GaN layers are presented. Dominant photoluminescence structures observed for these layers can be assigned to excitons bound to neutral impurities. Different methods such as temperature dependent evolution, high magnetic field and time resolved spectroscopy have been used to study the exciton line properties. For the p-type samples sharp lines are observed, assigned to the donor-acceptor recombination for differently distant pairs. The analysis of the optical transitions related to donors and acceptors is in reasonable agreement with the effective mass approximation. Electron phonon interaction was found to strongly affect the optical properties of GaN. The dominant intrinsic defect has been identified as a donor located at a nitrogen site.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Enhancement of the Excitonic Photoluminescence in $n^{+}$/i-GaAs by Controlling the Thickness and Impurity Concentration of the $n^{+}$ Layer
Autorzy:: Čerškus, A.
Nargelienė, V.
Kundrotas, J.
Sužiedėlis, A.
Ašmontas, S.
Gradauskas, J.
Johannessen, A.
Johannessen, E.
Tematy:: 78.55.-m
71.35.-y
71.55.Eq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1505489.pdf Link otwiera się w nowym oknie
Opis:: This communication presents the photoluminescence spectra of molecular beam epitaxially grown GaAs structures made from a 500 nm thick layer of intrinsic conductivity capped with a silicon doped layer with a film thickness ranging from 10 to 100 nm. Two different doping concentrations of the cap layer, $N_{Si} = 10^{17} cm^{-3}$ and $N_{Si} = 10^{18} cm^{-3}$, was considered. The results showed the excitonic line of i-GaAs layer enhancement. The intensity of excitonic line was about 160 times higher for the homojunction compared to the intrinsic conductivity epitaxial layer at liquid helium temperature. Possible mechanisms of the observed intensity enhancement in the $n^{+}$/i-GaAs homojunction are discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Photoluminescence Study of Bulk GaN Doped with Beryllium
Autorzy:: Jaworek, M.
Wysmołek, A.
Kamińska, M.
Twardowski, A.
Boćkowski, M.
Grzegory, I.
Tematy:: 78.55.Cr
71.55.-i
71.35.-y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2043722.pdf Link otwiera się w nowym oknie
Opis:: Photoluminescence of bulk GaN:Be grown by high pressure method is presented. The investigated crystals show well-resolved photoluminescence due to free and bound excitons similar to that observed for homoeptitaxial GaN layers. In addition to the excitonic transitions, pronounced luminescence band at 3.38 eV, due to Be acceptor, is observed. It was found that temperature behavior of this emission is typical of donor- and conduction band-acceptor transitions. The optical activation energy of Be acceptor is obtained to be of 60±15 meV.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Photoluminescence and Electron Paramagnetic Resonance Studies of Bulk GaN Doped with Gadolinium
Autorzy:: Lipińska, Z.
Pawłowski, M.
Żołnierowicz, H.
Wysmołek, A.
Palczewska, M.
Kamińska, M.
Twardowski, A.
Boćkowski, M.
Grzegory, I.
Tematy:: 78.55.Cr
71.55.-i
71.35.-y; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2046930.pdf Link otwiera się w nowym oknie
Opis:: Photoluminescence and electron paramagnetic resonance experiments on strain free GaN bulk crystals of wurtzite structure doped with gadolinium are reported. Efficient gettering of residual GaN donors by Gd was observed. Electron paramagnetic resonance showed that Gd ion incorporated into GaN lattice had Gd$\text{}^{3+}$(4f$\text{}^{7}$) configuration. The observed photoluminescence spectra were explained as due to intracenter Gd$\text{}^{3+}$(4f$\text{}^{7}$) transitions. No ferromagnetic behavior was detected.
Dostawca treści:: Biblioteka Nauki

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