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1

Peculiarities in optical response of hybrid-barrier GaSb/InAs/AlSb resonant tunneling diode structure

Dyksik M., Motyka M., Rygała M., Pfenning A., Hartmann F., Weih R., Worschech L., Höfling S., Sęk G.

Optica Applicata

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2021

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Vol. 51, nr 2

171--180

EN

We present comprehensive investigation of the optical properties of hybrid-barrier GaSb-based resonant tunneling structures, containing a bulk-like GaInAsSb absorption layer and two asymmetric type II GaSb/InAs/AlSb quantum wells. Methods of optical spectroscopy by means of Fourier-transformed photoluminescence and photoreflectance are employed to probe optical transitions in this complex multilayer system. Based on the comparison between the absorption-like and emission-like spectra (also in function of temperature) confronted with band structure calculations four main transitions could be resolved and identified. For one of them, there has been observed unusually strong linear polarization dependence never reported in structures of that kind. It has been interpreted as related to a transition at the GaSb/GaInAsSb interface, for which various scenarios causing the polarization selectivity are discussed.

2

Reverse engineering of AlxGa₁₋xAs/GaAs structures composition by reflectance spectroscopy

Wośko M., Paszkiewicz B., Tarnowski K., Ściana B., Radziewicz D., Salejda W., Paszkiewicz R., Tłaczała M.

Opto-Electronics Review

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2011

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Vol. 19, No. 4

418-424

EN

The paper presents the application of non-modulation reflectance method for composition profiling of epitaxial AlxGa₁₋xAs/GaAs structures. This non-destructive method is based on spectral measurements and theoretical reflectance spectrum matching. This is a very accurate and sensitive method of determining the Al composition in AlxGa₁₋xAs layers and structures with resolution down to 1 nm. In this work, the authors describe theoretic principles of this method and present experimental results of characterization of different AlGaAs structures to prove the potential of the worked out method.

3

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.

4

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.

5

Technology and properties of GaAs doping superlattices

Ściana B., Radziewicz D., Pucicki D., Tłaczała M., Sęk G., Poloczek P., Misiewicz J., Kováč J., Srnanek R., Christofi A.

Materials Science Poland

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2008

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Vol. 26, No. 1

71--78

EN

Heterojunction and doping superlattices are widely used in many advanced semiconductor devices such as resonant tunnelling diodes, optical modulators, cascade lasers, tunable light emitting diodes and photodetectors. These structures exhibit nonlinear electrooptical properties. Nonlinear processes are governed by the Franz-Keldysh effect and the band-filling effect in the n-i-p-i superlattices and by the quantum-confined Stark effect in the case of n-i-p-i multiple quantum well structures. The paper presents investigations of GaAs n-i-p-i and p-i-p-i doping superlattices grown by atmospheric pressure metal organic vapour phase epitaxy. The properties of the obtained structures were examined using: EC-V method, SIMS spectrometry, photoluminescence and photoreflectance spectroscopy.

6

Microphotoreflectance spectroscopy - a modulation technique with high spatial resolution

Sęk G., Podemski P., Rudno-Rudziński W., Gumienny Z., Misiewicz J.

Optica Applicata

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2007

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Vol. 37, nr 4

439-447

EN

There is presented an experimental setup for the measurements of photomodulated reflectivity spectra of low-dimensional semiconductor structures with a micrometer spatial (plane) resolution. The setup has been developed as an extended and improved version of a standard bright configuration, i.e., where the probe beam is provided directly by a broad band light source (e.g., halogen lamp) and then it is dispersed after being reflected off the sample. It gives typically the plane resolution, expressed by the spot size of the beams on the sample surface, on the level of single millimetres. Introducing optics, based on a long working distance and a high numerical aperture microscope objective, has allowed decreasing the spot size by three orders of magnitude into the micrometer range for both the probe and the pump beams. The optimization of microphotoreflectance signal to noise ratio has made it possible to detect the normalized reflectivity coefficient changes (?R/R) from an ultrathin single quantum well formed of the wetting layer in the structure with self-assembled InAs/GaAs quantum dots and from single pillar microresonators of the lateral sizes in the range of single micrometers.

7

Photoreflectance spectroscopy of thick GaN layers grown by hydride vapour phase epitaxy technique

Syperek M., Kudrawiec R., Misiewicz J., Korbutowicz R., Paszkiewicz R., Tłaczała M.

Optica Applicata

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2005

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Vol. 35, nr 3

529-535

EN

The room temperature photoreflectance (PR) spectroscopy was used to investigate thick GaN epitaxial layers. The GaN layers were grown by hydride vapour phase epitaxy (HVPE) technique and compared to thin GaN layer grown by metalorganic vapour phase epitaxy (MOVPE) technique on AlN buffer layer. We observed energy red shift of the PR resonance for HVPE GaN layers compared with MOVPE GaN layer. This blue shift is due to reduction of the strain in HVPE layer. In addition, weak PR features related to Franz-Keldysh oscillations (FKO) have been observed. The electric field determined from the FKO period is 28 and 71 kV/cm for MOVPE and HVPE layers, respectively.

8

Optical properties of InGaAsP quantum well for infrared emission investigated by modulation spectroscopy

Podhorodecki A., Andrzejewski J., Motyka M., Kudrawiec R., Misiewicz J., Wójcik J., Robinson B. J.

Optica Applicata

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2005

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Vol. 35, nr 3

509-515

EN

Modulation spectroscopy, i.e., photoreflectance (PR) and contactless electroreflectance (CER) are very powerful techniques to investigate optical properties of nanostructures. These techniques together with photoluminescence spectroscopy were used for investigation of optical properties of InGaAsP quantum well with infrared emission at 1.55 um. Samples used in this study were grown by gas source molecular beam epitaxy (MBE) on n-doped (100) InP substrate. Based on the numerical calculations the origin of observed optical transitions has been explained and the energy structure of the investigated samples has been proposed.

9

Photoreflectance and photoluminescence of thick GaN layers grown by HVPE

Kudrawiec R., Korbutowicz R., Paszkiewicz R., Syperek M., Misiewicz J.

Opto-Electronics Review

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2004

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Vol. 12, No. 4

435-439

EN

Very thick (up to 100 µm) GaN layers grown by HVPE are investigated by photoreflectance (PR) and photoluminescence (PL) spectroscopies. The layers were deposited on a GaN buffer layer which was grown on a c-plane sapphire substrate by MOVPE. Both, N- and Ga-polar layers were selected to these investigations. We have observed a strong dependence of the optical properties on the polarity of GaN surface. We have obtained that the bandgap-related emission for Ga-polar layers is stronger and narrower than the emission for N-polar layers. Also, significant differences have been found in PR spectra of the two type layers. In the case of Ga-polar layer a broad PR resonance with Franz-Keldysh oscillation (FKO) related to the surface electric field (215 kV/cm) has been observed, while in the case of N-polar layer narrow resonances have been found as being predominant. No-FKO for N-polar layer indicates that the surface electric field for this layer is weak. It means that the surface barrier for N-polar GaN is much smaller than for Ga-polar GaN layer.

10

Semiconductor heterostructures and device structures investigated by photoreflectance spectroscopy

Misiewicz J., Sitarek P., Sęk G., Kudrawiec R.

Materials Science

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2003

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Vol. 21, No. 3

263-318

EN

In this review paper, we present the photoreflectance spectroscopy as a powerful tool for investigations of bulk semiconductors and semiconductor heterostructures. We discuss the application of this spectroscopy technique to investigate various properties of semiconductors, including: the composition of multinary compounds, distribution of the built-in electric field and the influence of perturbation such as temperature, strain, pressure; low-dimensional structures such as quantum wells, multiple quantum wells and superlattices, quantum dots; and the structures of semiconductor devices like transistors and vertical/planar light emitting laser structures.

11

Photoreflectance spectroscopy of low-dimensional semiconductor structures

Misiewicz J., Sitarek P., Sęk G.

Opto-Electronics Review

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2000

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Vol. 8, No. 1

1-24

EN

In this paper, we present the applications of photoreflectance spectroscopy for investigations of low-dimensional, semiconductor structures. We briefly introduce the theoretical background of this technique including the line-shape expressions related to semiconductor microstructures. We show examples of photoreflectance investigations of two-dimensional structures such as quantum wells, multiple quantum wells and superlattices, one-dimensional structures-guantum wires, and quasi zero-dimensional structures-quantum dots. Finally, we concentrate our attention on investigations of the structures of semiconductor devices like high electron mobility transistors, heterojunction bipolar transistors and vertical / planar light emitting lasers structures.