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Optymalizacja obszaru aktywnego międzypasmowego lasera kaskadowego

Ryczko K.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 8

24--26

PL

W tym artykule przedstawiono teoretyczne badania struktury pasmowej studni kwantowych II rodzaju InAs/GaInSb i InAs/GaAsSb, które mogą być stosowane jako obszary aktywne międzypasmowych laserów kaskadowych, emitujących w szerokim zakresie średniej podczerwieni. Stosując wielopasmowy model kp obliczono zależność energii oraz siły oscylatora fundamentalnego przejścia optycznego od grubości warstw stanowiących studnie kwantowe dla elektronu.

XX

In this paper, we present theoretical investigations of the band structure of type-II InAs/GaInSb and InAs/GaAsSb quantum wells dedicated for the active region of interband cascade lasers emitting in a broad range of mid infrared. We utilize the multiband kp theory in order to calculate the dependence of the energy and oscillator strength of the fundamental optical transition on the thickness of particular layers confining electrons.

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Oscillator strength of optical transitions in InGaAsN/GaAsN/GaAs quantum wells

Mika A, Sek G, Ryczko K, Kozub M, Musial A, Marynski A, Misiewicz J, Langer F, Höfling S, Appel T, Kamp M, Forchel A

Optica Applicata

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2013

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Vol. 43, nr 1

53--60

EN

Experimental and theoretical considerations and results on the effect of nitrogen incorporation on the oscillator strength of optical transitions in InGaNAs/GaAs quantum wells (QWs) are presented. Therefore, a set of dilute nitride quantum well structures was grown by molecular beam epitaxy. Optical investigation via spectroscopic methods have been performed at various temperatures for both the as-grown samples, and after rapid thermal annealing. The fundamental transition energy and its oscillator strength vs. the QW composition have been systematically investigated. Additionally, the effect of the bandgap discontinuities on the transitions intensity has also been considered. The experimental data have been confronted with the band structure calculations within the effective mass approximation employing a two level repulsion model for the nitrogen-containing structures. The obtained results are crucial for possible future applications employing the quantum well in cavity structures and bringing the practical exploitation of quantum electrodynamics phenomena to the telecommunication spectral range.

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Above GaSb barrier in type II quantum well structures for mid-infrared emission detected by Fourier-transformed modulated reflectivity

Motyka M., Janiak F., Ryczko K., Sęk G., Misiewicz J., Bauer A., Weih R., Höfling S., Kamp M., Forchel A.

Opto-Electronics Review

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2011

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Vol. 19, No. 2

137-139

EN

Modulation spectroscopy in its Fourier-transformed mode has been employed to investigate the optical properties of broken gap 'W'-shaped GaSb/AlSb/InAs/InGaSb/InAs/AlSb/GaSb quantum well structures designed to emit in the mid infrared range of 3-4 µm for applications in laser-based gas sensing. Besides the optical transitions originating from the confined states in the type II quantum wells, a number of spectral features at the energy above the GaSb band gap have been detected. They have been analyzed in a function of InAs and GaSb layer widths and ultimately connected with resonant states in the range of AlSb tunneling barriers.

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Optyczne właściwości supersieci GaAs/AlGaAs badane za pomocą spektroskopii modulacyjnej

Janiak F., Motyka M., Sęk G., Ryczko K., Misiewicz J., Kosiel K., Bugajski M.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 10

46-48

PL

Spektroskopię modulacyjną- fotoodbicie zastosowano do badania optycznych i strukturalnych właściwości supersieci AlGaAs/GaAs. Otrzymano widma fotoodbiciowe bogate w linie spektralne związane z procesami absorpcji między poszczególnymi stanami kwantowymi w badanych supersieciach. Zmierzone linie spektralne zidentyfikowane zostały na podstawie obliczeń struktury pasmowej w modelu masy efektywnej. Przeprowadzone pomiary pozwoliły potwierdzić założone w procesie wzrostu składy i grubości poszczególnych warstw studni i barier. Ponadto wykazano bardzo dużą jednorodność wytwarzanych 2-calowych płytek jak również wysoką powtarzalność procesów technologicznych.

EN

Modulation spectroscopy - photoreflectance has been applied for optical investigation of AlGaAs/GaAs superlattices. Optical features obtained in photoreflectance spectra associated with the transitions between confined levels in investigated superlattices have been recognized and analyzed by calculation performed in effective mass approximation formalism. In addition, there has been demonstrated a high uniformity of investigated 2 inch wafers and also high repeatability of the growth process.

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Photoreflectance study of Al0.45Ga0.55As/GaAs superlattice: optical transitions at the miniband .GAMMA. and .PI. points

Motyka M., Sęk G., Janiak F., Ryczko K., Misiewicz J., Kosiel K., Bugajski M.

Optica Applicata

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2009

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Vol. 39, nr 4

897-902

EN

In this paper, we present the results of photoreflectance (PR) investigation of an Al0.45Ga0.55As/GaAs superlattice (SL). The modulation spectra have revealed a number of features at both room and low temperature (10 K) which could be associated with the optical transitions between the minibands of the superlattice. Based on calculations within the effective mass approximation they have been identified as transitions between the miniband edges, i.e., the so-called ? and ? points, respectively, including the high index transitions and those related to the light holes. Tuning the structure parameters around the nominal ones treated as semi-free in the theoretical considerations allowed the growth accuracy of such a complex system to be verified.

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Optical methods used to optimise semiconductor laser structures with tunnel injection from quantum well to InGaAs/GaAs quantum dots

Rudno-Rudzinski W., Ryczko K., Sęk G., Syperek M., Misiewicz J., Pavelescu E. M., Gilfert C., Reithmaier J. P.

Optica Applicata

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2009

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Vol. 39, nr 4

923-932

EN

We present the results of optical measurements performed on structures consisting of an InGaAs quantum well (QW), separated by a thin barrier from a layer of self-assembled InGaAs quantum dots (QDs). Such a kind of design is called a tunnel injection structure, because its functionality is based on the tunnelling of carriers from a QW to QDs, preferably with the assistance of optical phonons. In this approach, the injector QW serves as a reservoir of the carriers (due to much higher efficiency of carrier collection) and alleviates the problem of long relaxation times needed for carriers to reach the QDs ground state. In order to investigate the structures several complementary experimental techniques are applied. Photoreflectance, an absorption-like modulation spectroscopy, gives the information about the optical transitions and the electronic structure. The temperature evolution of photoluminescence allows emission efficiency and carrier losses to be determined. Photoluminescence excitation probes directly the carrier transfer from QW to the dots. The interpretation of the results is supported by the calculations in the envelope function formalism. It has been found out that the wavefunction position of the lowest lying levels depends on the QW parameters and thus different regimes of tunnelling are proposed.

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Photoreflectance study of coupling effects in double quantum wells

Sęk G., Ryczko K., Kubisa M., Misiewicz J., Koeth J., Forchel A.

Opto-Electronics Review

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1999

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Vol. 7, No. 2

117-119

EN

A double quantum well (DQW) molecular beam epitaxy (MBE) grown GaAs/AlxGa1-xAs structure was studied. To investigate the coupling effects in such a system 1 monolayer (ML) thick AlAs barrier was inserted at the centre of the GaAs/AlxGa1-xAs single well. Due to the strong coupling between wells each confined state splits into two : symmetric and antisymmetric ones. At room temperature photoreflectance (PR) spectrum features related to transitions between all these states were observed. Theoretical considerations based on the envelope function approximation were performed to obtain the energies of expected optical transitions. An excellent agreement between experiment and theory was obtained.