Wyniki wyszukiwania - BazTech

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Struktura pasmowa i optyczne właściwości supersieci InAs/GaSb

Machowska-Podsiadło E., Jasik A., Pierściński K., Bugajski M.

Elektronika : konstrukcje, technologie, zastosowania

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2010

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Vol. 51, nr 10

30-32

PL

W pracy przedstawiono wyniki obliczeń stanów elektronowych w supersieciach II rodzaju wykonane dla trzech próbek, złożonych z 30 sekwencji warstw o grubości nominalnej 8 ML InAs/8 ML GaSb oraz zmierzone dla nich widma luminescencji (PL). Badane supersieci zostały wykonane metodą epitaksji z wiązki molekularnej na podłożu GaSb. Prezentowane widma PL są zgodne z wynikami przedstawionymi w pracy [1]. Krawędź absorpcji badanych supersieci otrzymano na poziomie 4,26 µm. Wyniki eksperymentu porównano z wynikami obliczeń numerycznych, wykonanych metodą opisaną, w pracy [2]. Stany elektronowe supersieci wyznaczono z uwzględnieniem mieszania się stanów dziur ciężkich (HH) oraz dziur lekkich (LH) na powierzchniach międzyfazowych pomiędzy warstwami supersieci. W obliczeniach uwzględniono zjawisko nieparaboliczności pasm, związane z wąską, przerwą energetyczną arsenku indu. Wyniki przeprowadzonych symulacji korespondują z wynikami otrzymanymi na podstawie eksperymentu.

EN

In the work we present the results of the electron states calculation in the type-II superlattices. Calculations were performed for the three samples with the 30 layer sequence with the nominal thickness 8 ML InAs/8 ML GaSb. We also present the photoluminescence (PL) spectra measured for the investigated structures. The superlattices were grown on GaSb substrate with the use of molecular beam epitaxy. The measured PL spectra are in a good agreement with the results presented in the work [1]. The cutt-off wavelength of the investigated superlattices was obtained on the level of 4,26 µm. The experimental results were compared with the results of the numerical calculations which were performed with the use of the method presented in the work [2]. The electron states in the superlattice were calculated taking into account the effect of heavy hole and light hole mixing at the interfaces between InAs and GaSb layers. In the calculations we considered the effect of the nonparabolicity which is the consequence of the narrow InAs band gap. The results of calculation correspond with the results obtained from the experiment.

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Electronic miniband formation in a two-dimensional semiconductor superlattice

Kłos J. W., Krawczyk M

Materials Science Poland

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2008

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Vol. 26, No. 4

965--970

EN

We investigate a system of periodically arranged uniform rods, regarded as a two -dimensional superlattice. The assumed arrangement of rods within a supercell allows to express the two-dimensional effective potential as a sum of two terms depending on either x or y coordinate only. The structure consist of two square lattices of square rods embedded in the matrix material. Rods in one lattice act as potential barriers for electrons, and those in the other as potential wells. The separation of the effective potential is shown not to imply Hamiltonian separation in the envelope function approximation. The energy spectra of the conduction band are computed for the numerical solution as well as for the analytical one, the latter wrongly assuming the separation of the Hamiltonian. The band structures computed in the two cases differ in band position and width.

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The 61Π u state of Na2 molecule

Grochola A., Kubkowska M. K., Jastrzębski W., Kowalczyk P.

Optica Applicata

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2006

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Vol. 36, nr 4

s. 469--473

EN

Excitation spectra of sodium dimer were analysed within the range 34200–36400 cm–1. The experiment was done using polarisation labelling spectroscopy technique. In the spectral region under investigation we found several vibrational progressions belonging to a single band system having the ground state of Na2 as the lower state. The upper state was of 1Π u symmetry as indicated by the presence of Q lines in the spectrum and basing on theoretical calculations it was identified as the 61Π u (3s+4f ) state. The Dunham coefficients and potential curve characterising this state were deduced from the observed spectra.

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Investigation of a highly excited electronic 1Π state of NaLi molecule

Bang N. H., Grochola A., Jastrzebski W., Kowalczyk P., Salami H.

Optica Applicata

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2006

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Vol. 36, nr 4

s. 499--504

EN

We report on our investigation of the excitation spectra of the NaLi molecule in the energy range 31000–33900 cm–1. A polarisation labelling technique is used to ensure rotational resolution of the spectra and to enable unambiguous assignment of the NaLi transitions. A hitherto unknown electronic state of 1Π symmetry is observed. Major molecular constants of the state are determined and its potential curve constructed using the inverted perturbation approach method.