Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 19

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Structural and Optical Properties of Antimony-Containing Epitaxial Layers Grown on GaSb by MOCVD

100%
Wesołowski M., Strupiński W.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue S
S-62-S-64
EN
Experimental results on MOCVD epitaxy of some antimonides on GaSb substrates are presented. Specific technological problems, which effect in narrow window of process parameters, were overcome and good quality of GaSb/GaSb, InGaSb/GaSb and InGaAsSb/GaSb layers was obtained. Structural, optical and electrical characterisation data are shown and discussed. Developed technology can state a ground work for realisation of antimonide-based optoelectronic devices.
2
Content available remote

MOCVD Growth of InP-Related Materials Using TEA and TBP

100%
Czub M., Strupiński W.
Acta Physica Polonica A
|
1995
|
vol. 88
|
issue 4
695-698
EN
High quality epitaxial layers of GaAs, InP, AlAs, InGaAs, InGaP, In­GaAlP have been grown by low-pressure metalorganic chemical vapor depo­sition using TMIn, TMGa, TMAl and the less hazardous group V precursors, ΤΒA, TBP. Excellent morphology was obtained for GaAs and InP in the temperature ranges of 570-650°C and 520-650°C, respectively. The V/III ratio as low as 1.5 was used to grow epilayers of InP. The 77 K mobility of InGaAs lattice matched to InP (grown with ΤΒA) was 72360 cm^{2}/(V s) for n = 1.5 × 10^{15}/cm^{-3} and a thickness of 2 μm. Comparable photolumines­cence parameters of InGaP between layers grown with TBP and PH_{3} were achieved, but for InGaAlP (TBP) photoluminescence intensity was signifi­cantly lower than for InGaAlP (PH_{3}). The promising results allow one to apply of ΤΒA and TBP for developing of device structures.
3
Content available remote

In Situ Raman Spectroscopy of Solution-Gated Graphene on Copper

81%
Binder J., Stępniewski R., Strupiński W., Wysmołek A.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
360-363
EN
We present a solution-gated in situ Raman spectroscopy approach, which enables the electrical characterization of graphene on a copper substrate without the need of a transfer process. The application of a voltage across the solution resulted in a shift of the Raman G-band without a significant shift of the 2D band. This observation allowed for the separation of the effects of strain and doping. Based on the G and 2D band shifts we show that we can manipulate the n-type carrier concentration of graphene directly on the copper substrate in a range from about 8× 10¹² cm¯² to about 1.5× 10¹³ cm¯².
4
Content available remote

Microscopic Investigation of SiC Epitaxial Layers οn On-Axis 4H-SiC Substrates Using Kelvin Probe Force Microscopy

81%
Kościewicz K., Bożek R., Strupiński W., Olszyna A.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue S
S-69-S-71
EN
We report on Kelvin probe force microscopy and electron backscatter diffraction measurements of 3C-SiC epitaxial layers grown on exactly oriented Si-face 4H-SiC (0001) substrates in a horizontal hot-wall chemical vapor deposition reactor, in the temperature range from 1150°C to 1620°C, under H_{2} or H_{2} +SiH_{4} atmosphere. The investigated layers were doped with nitrogen (for n-type) and aluminium (for p-type). The electron backscatter diffraction analysis revealed structure of polytype 3C blocks with a relative rotation of 60 and/or 120°. The Kelvin probe force microscopy measurements revealed cubic substructure as a equilateral triangle objects contrast which is characteristic of 3C silicon carbide polytype. The surface potential contrast was found to be dependent on the type and concentration of doping, which could be explained in terms of the impurities accumulation at block boundaries.
5
Content available remote

Transport of Photoexcited Electron-Hole Plasma in GaN/AlGaN Quantum Well

81%
Korona K., Caban P., Strupiński W.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
927-929
EN
We report spatially resolved photocurrent measurements showing transport of excitation on long distances in plane of a 6 nm GaN/Al_{0.1}Ga_{0.9}N quantum well. The strong field present in nitrides (due to large spontaneous and piezoelectric polarizations) leads to lower recombination rates of electrons and holes, so in the case of electron-hole pairs excited by light, relatively long-lived electron-hole plasma could be generated. In the case of the investigated quantum well, lifetime of few μs was expected. The thermal measurements showed that barriers were low enough, so all excited carriers could reach the electrode (thermal activation energy of 0.11 eV was found). The diffusion length for unbiased structure was about 40 μm. It was observed that the charge transport could be clearly accelerated by bias. In the biased quantum well, the transport range was of the order of 100 μm under both positive and negative bias. The reported effect of long transport range is very important for electronic devices made on the GaN/AlGaN structures.
6
Content available remote

Defect Transformations in Ion Bombarded InGaAsP

71%
Ratajczak R., Turos A., Stonert A., Nowicki L., Strupiński W.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 1
136-139
EN
Damage buildup and defect transformations at temperatures ranging from 15 K to 300 K in ion bombarded InGaAsP epitaxial layers on InP were studied by in situ Rutherford backscattering/channeling measurements using 1.4 MeV ^4He ions. Ion bombardment was performed using 150 keV N ions and 580 keV As ions to fluences ranging from 5 × 10^{12} to 6 × 10^{14} at./cm^2. Damage distributions were determined using the McChasy Monte Carlo simulation code assuming that they consist of randomly displaced lattice atoms and extended defects producing bending of atomic planes. Steep damage buildup up to amorphisation with increasing ion fluence was observed. Defect production rate increases with the ion mass and decreases with the implantation temperature. Parameters of damage buildup were evaluated in the frame of the multi-step damage accumulation model. Following ion bombardment at 15 K defect transformations upon warming up to 300 K have also been studied. Defect migration beginning above 100 K was revealed leading to a broad defect recovery stage with the activation energy of 0.1 eV for randomly displaced atoms and 0.15 eV for bent channels defects.
7
Content available remote

Transmission Electron Microscopy and Luminescence Studies of Quantum Well Structures Resulting from Stacking Fault Formation in 4H-SiC Layers

71%
Borysiuk J., Wysmołek A., Bożek R., Strupiński W., Baranowski J.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 5
1067-1072
EN
Transmission electron microscopy and photoluminescence studies of quantum well structures related to stacking faults formation in 4H-SiC homoepitaxial layers are reported. The investigated 4H-SiC layers were deposited on 8° misoriented Si-terminated (0001) surface of high quality 4H-SiC substrate. It is found that the planar defects created by direct continuation from the SiC substrates are cubic 3C-SiC stacking faults. These defects are optically active, giving rise to characteristic luminescence band in the spectral range around 2.9 eV, which consist of several emission lines. The observed energy and intensity pattern of this emission is discussed of in terms of single, double and multiple quantum wells formed from neighboring 3C-SiC SF layers embedded in 4H-SiC material.
8
Content available remote

CVD Growth of Graphene Stacks on 4H-SiC (0001) Surface - X-ray Diffraction and Raman Spectroscopy Study

71%
Tokarczyk M., Kowalski G., Grodecki K., Urban J., Strupiński W.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 5
768-771
EN
Features associated with short and prolonged growth time in the chemical vapor deposition process of growth of graphene stacks on SiC (0001) substrate are reported. In particular general bimodal (as far as d_{002} interlayer spacing is concerned) distribution of graphene species across the surface of the samples is observed. It consists of thin few layer graphene coverage of most of the sample surface accompanied by thick graphite-like island distribution. It points to the two independent channels of graphene stacks growth with two characteristic growth rates.
9
Content available remote

Topographic and Reflectometric Investigation of Crystallographic Defects and Surface Roughness in 4H Silicon Carbide Homoepitaxial Layers Deposited at Various Growth Rates

62%
Wierzchowski W., Wieteska K., Mazur K., Kościewicz K., Balcer T., Strupiński W., Paulmann C.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 4
915-919
EN
Undoped 4H silicon carbide epitaxial layers were deposited by means of CVD method with growth rates of 2 μm/h, 5 μm/h and 11 μm/h at 1540°C on n-doped 8°, 4° and 0° off-cut 4H-SiC (00·1) substrates. The structural defects were studied before and after growth of the epitaxial layers by means of conventional Lang topography, synchrotron white beam and monochromatic beam topography and by means of X-ray specular reflectometry. The topographic investigations confirmed the continuation of the dislocations in the epitaxial deposit on the 8° and 4° off-cut substrates without new extended defects. The important difference occurred in the surface roughness of the epitaxial layers, which increased for higher growth rates. The epitaxial layers grown on 0° off-cut substrates at analogous condition contained usually other SiC polytypes, but the influence of the growth rate on the distribution of the polytypes was observed.
10
Content available remote

Role of the Thermal Stress on the Magnetophonon Peak Structure in the Parallel Transport of the GaAs/AlGaAs Multiple Quantum Wells

62%
Tomaka G., Cebulski J., Sheregii E., Ściuk W., Strupiński W., Dobrzański L.
Acta Physica Polonica A
|
1998
|
vol. 94
|
issue 3
597-602
EN
The magnetophonon resonance in parallel transport of two types multiple quantum wells was studied. The transverse magnetoresistance was measured in pulsed magnetic fields up to 30 T (within temperature region from 77 to 340 K). A fine structure of magnetophonon resonance peaks which depends on temperature and does not depend on the type of multiple quantum wells, was observed. This effect could be attributed to two phenomena: contribution of barrier phonons and influence of thermostresses.
11
Content available remote

Comparative Morphological Analysis of Graphene on Copper Substrate obtained by CVD from a Liquid Precursor

62%
Weiss M., Walkowiak M., Wasiński K., Półrolniczak P., Kokocińska B., Strupiński W.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 6
1497-1506
EN
Graphene film has been produced on untreated Cu substrate by a chemical vapor deposition technique in ambient pressure with liquid ethanol serving as the carbon precursor. The obtained material has been subjected to morphological study, directly on Cu substrate, by means of optical microscopy, scanning electron microscopy, atomic force microscopy, and a detailed Raman analysis. As a benchmark material, graphene obtained on Cu by a conventional CVD from gaseous methane was used. This simple experimental setup has proved to enable obtaining large area graphene samples with nearly 100% substrate coverage and large domains of one carbon layer. As compared to graphene from gaseous precursor, the presented approach resulted in visibly more defects and impurities. These imperfections are due to more complex precursor molecular structure and lack of Cu pretreatment with hydrogen, the later cause being easy to eliminate in course of further optimization of the method. The described approach can be regarded as a viable, low-cost, and experimentally simple alternative for the existing techniques of producing large area graphene. By providing direct comparison with the conventional method, the paper's intention is to provide deeper insight and to fill gap in the understanding of mechanisms involved in graphene formation on copper.
12
Content available remote

Graphene Based Flow Sensors

62%
Kaźmierczak P., Binder J., Boryczko K., Ciuk T., Strupiński W., Stępniewski R., Wysmołek A.
|
|
vol. 126
|
issue 5
1209-1212
EN
We report on attempts to produce a graphene based liquid flow sensor. Our results indicate that modifications of the electric double layer, formed in the vicinity of the graphene surface, dominate over mechanisms responsible for liquid flow-induced voltage/current generation. Several graphene structures were tested in different measurement configurations, aimed to maximize the generated signal amplitude and its stability. Some realizations of working devices in water as well as in aqueous solutions of NaCl or HCl are presented.
13
Content available remote

ESR Spectroscopy of Graphene with Adsorbed NaCl Particles

62%
Karpierz E., Drabińska A., Bożek R., Kaźmierczak P., Wysmołek A., Kamińska M., Strupiński W.
|
|
vol. 126
|
issue 5
1187-1189
EN
Due to its peculiar properties graphene is a good candidate for sensor materials. Therefore, it is important to study influence of different fluids on graphene layer. The presented studies showed pinning of NaCl microcrystals to graphene surface after immersing graphene in NaCl solution and subsequent careful rinsing with distilled water. The atomic force microscopy images revealed presence of many NaCl-related structures over 100 nm high on graphene surface. The electron spin resonance spectrum for magnetic field perpendicular to the graphene layer consisted of several lines originating from NaCl. The pinning of NaCl microcrystals resulted in increase of electron scattering, as confirmed by the Raman spectroscopy (the increase of intensity of D and D' bands) and weak localization measurement (the decrease of coherence length).
14
Content available remote

Functional Properties of Monolayer and Bilayer Graphene Hall-Effect Sensors

62%
Kachniarz M., Petruk O., Salach J., Ciuk T., Strupiński W., Bieńkowski A., Szewczyk R.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 5
1250-1253
EN
The paper describes the design, development, and investigation of a new type of Hall-effect sensors of a magnetic field made of graphene. The epitaxial growth of high-quality graphene structures was performed using a standard hot-wall CVD reactor, which allows for easy integration with an existing semiconductors production technologies. The functional properties of developed Hall-effect sensors based on graphene were investigated on special experimental setup utilizing Helmholtz coils as a source of reference magnetic field. Monolayer and quasi-free-standing bilayer graphene structures were tested. Results presented in the paper indicate that graphene is very promising material for development of Hall-effect sensors. Developed graphene Hall-effect sensor exhibit highly linear characteristics and high magnetic field sensitivity.
15
Content available remote

InGaN QW in External Electric Field Controlled by Pumping of 2D-Electron Gas

62%
Korona K., Drabińska A., Surowiecka K., Wołowiec L., Borysiuk J., Caban P., Strupiński W.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 5
1179-1186
EN
We present investigations of GaInN/GaN/AlGaN structure containing cavity designed so that the electric field inside it can be changed by illumination. Numerical calculations show that illumination can change carrier distributions and consequently change the field and potential. The electric field influences properties of a quantum well placed in the cavity. We confirmed experimentally that the electric field controlled by external bias or by optical pumping, can change energy and occupation of electronic states in the quantum well. The quantum well energy could be changed of about 80 meV by voltage and 15 meV by illumination.
16
Content available remote

Transport Properties of Disordered Graphene Layers

62%
Gryglas-Borysiewicz M., Jouault B., Tworzydło J., Lewińska S., Strupiński W., Baranowski J.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
838-840
EN
Samples consisting of a few layers of graphene obtained by thermal decomposition of SiC were studied by means of transport experiments at 4 K and in a magnetic field up to 7 T. Transport data show that the samples have a two-dimensional character. Magnetoresistance has an approximately linear character at high magnetic fields, which has been previously observed in graphite samples, and a negative magnetoresistance, at low magnetic fields. The transverse resistivity ρ_{xy} is nonlinear as a function of B, which can be described using a many-carrier model.
17
Content available remote

Influence of SiC Surface Preparation on Homoepitaxial Growth; X-ray Reflectometric Studies

52%
Mazur K., Wierzchowski W., Wieteska K., Hofman W., Sakowska H., Kościewicz K., Strupiński W., Graeff W.
|
|
issue 2
272-276
EN
X-ray reflectometric and diffraction topographic methods were applied for examination of 4H and 6H silicon carbide substrates finished with various regimes, as well as, silicon carbide epitaxial layers. The investigations indicated a very good quality of the substrate surfaces finished with the process established at the Institute of Electronic Materials Technology, which provided the surface roughness σ = 0.55 ± 0.07 nm for 4H-SiC wafers. These values were better than those of substrate wafers offered by many commercial producers. The surface roughness was decreased during the initial high temperature etching to σ = 0.22 ± 0.07 nm. A relatively good structural quality was confirmed in the case of 4H epitaxial wafers deposited on the substrates prepared from the crystals manufactured at the IEMT, with the 8° off-cut from the main (001) plane.
18
Content available remote

Optical Absorption and Raman Scattering Studies of Few-Layer Epitaxial Graphene Grown on 4H-SiC Substrates

52%
Grodecki K., Drabińska A., Bożek R., Wysmołek A., Korona K., Strupiński W., Borysiuk J., Stępniewski R., Baranowski J.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
835-837
EN
Optical absorption and Raman scattering studies of few-layer epitaxial graphene obtained by high temperature annealing of carbon terminated face of 4H-SiC(000-1) on-axis substrates are presented. Changing the pressure and annealing time, different stages of the graphene formation were achieved. Optical absorption measurements enabled us to establish average number of graphene layers covering the SiC substrate. Raman scattering experiments showed that integrated intensity of the characteristic 2D peak positively correlated with the number of graphene layers deposited on the SiC substrate. The spectral width of the 2D peak was found to decrease with the number of the deposited graphene layers.
19
Content available remote

Terahertz Detection by the Entire Channel of High Electron Mobility Transistors

42%
Sakowicz M., Łusakowski J., Karpierz K., Knap W., Grynberg M., Köhler K., Valusis G., Gołaszewska K., Kamińska E., Piotrowska A., Caban P., Strupiński W.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 5
1343-1348
EN
GaAs/AlGaAs and GaN/AlGaN high electron mobility transistors were used as detectors of THz electromagnetic radiation at liquid helium temperatures. Application of high magnetic fields led to the Shubnikov-de Haas oscillations of the detection signal. Measurements carried out with a simultaneous modulation of the intensity of the incident THz beam and the transistor gate voltage showed that the detection signal is determined by the electron plasma both in the gated and ungated parts of the transistor channel. This result is of importance for understanding the physical mechanism of the detection in high electron mobility transistors and for development of a proper theoretical description of this process.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.