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Wyszukujesz frazę "Stępniewski, J." wg kryterium: Autor


Tytuł:
Investigation of Quantum Dot Structures Grown by MOCVD in InAs/GaAs System
Autorzy:
Jasiński, J.
Bożek, R.
Stępniewski, R.
Kozubowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1991544.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.-a
61.16.Bg
Opis:
Layers of InAs quantum dots grown on [100] GaAs substrates were characterised by photoluminescence and investigated by transmission electron microscopy. Two types of InAs islands were observed in these layers. The islands of the first type had mainly a form of big, elongated pyramids. Most of them were found to be dislocated. On the other hand, the islands of the second type were real self-assembled, coherent quantum dots giving rise to a characteristic photoluminescence band.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 369-373
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exciton in 2D Cubic Inclusion in Hexagonal GaN
Autorzy:
Suffczyński, M.
Stępniewski, R.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1968430.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
78.66.-w
61.72.Nn
Opis:
An inclusion of cubic GaN in an otherwise hexagonal matrix is considered to be equivalent to an effective quantum well. The exciton binding energy in a quantum well of a finite potential barrier height in the conduction and valence bands is calculated in the effective mass approximation with a variational envelope function type of Bastard and Takagahara. The exciton binding energy and the energy of exciton recombination line are computed, as a function of the well width, for realistic potential barrier heights and band-offset ratios.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 993-996
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In Situ Raman Spectroscopy of Solution-Gated Graphene on Copper
Autorzy:
Binder, J.
Stępniewski, R.
Strupiński, W.
Wysmołek, A.
Powiązania:
https://bibliotekanauki.pl/articles/1033795.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.65.Pq
78.67.Wj
73.30.+y
Opis:
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.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 360-363
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Pinning of the Fermi Level by Germanium A$\text{}_{1}^{0}\text{}^{/}\text{}^{+}$ Deep Donor State in GaAs Codoped with Ge and Te
Autorzy:
Słupiński, T.
Nowak, G.
Przybytek, J.
Stępniewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1929765.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
Opis:
We present the possibility of GaAs:Ge,Te crystals growth from the melt (liquid encapsulated Czochralski method) with partially occupied, at ambient pressure, the A$\text{}_{1}$ localized electronic state of Ge$\text{}_{Ga}$ impurity. In as-grown crystals the amphotericity of Ge and creation of defects (deep acceptor complexes, precipitates etc.) during cooling after growth limit the free electron concentration below the value necessary to populate the A$\text{}_{1}^{0}\text{}^{/}\text{}^{+}$ level. Special annealing of the samples, which enlarges the free electron concentration, was used. The occupation of A$\text{}_{1}^{0}\text{}^{/}\text{}^{+}$ level, at ambient pressure, was observed by pressure dependent Hall effect measurements.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 807-811
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Studies of Defects in Graphene Grown on SiC
Autorzy:
Grodecki, K.
Bożek, R.
Borysiuk, J.
Strupinski, W.
Wysmolek, A.
Stępniewski, R.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047919.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.48.Gh
78.30.Fs
Opis:
The Raman scattering studies of multi-layer graphene obtained by high temperature annealing of carbon terminated face of 4H-SiC(000-1) substrates are presented. Intensity ratio of the D and G bands was used to estimate the average size of the graphene flakes constituting carbon structures. The obtained estimates were compared with flake sizes from atomic force microscopy data. We found that even the smallest structures observed by atomic force microscopy images are much bigger than the estimates obtained from the Raman scattering data. The obtained results are discussed in terms of different average flake sizes inside and on the surface of the multi-layer graphene structure, as well as different type of defects which would be present in the investigated structures apart from edge defects.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 595-596
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Evolution of the Microluminescence Energy οf GaN/AlGaN Quantum Dots
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791354.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Time evolution of the microphotoluminescence from low-density GaN/$Al_{x}Ga_{1-x}N$ quantum dots grown by metal organic chemical vapor deposition using in situ etching of AlGaN is presented. The observed effect is related to the energy changes that begin immediately after sample illumination with the exciting laser light and saturate after some time. Typically, the luminescence energy decreases and the change is exponential with characteristic times in a range between several dozen and several hundred seconds. However, sometimes we observed the energy increase with characteristic times in a range between several and a few hundred seconds. The obtained results are discussed in terms of the metastable change of the electric field, induced by spontaneous polarization present in GaN/AlGaN structure (in the growth direction), and strain- or defect-induced changes of the electric field in the vicinity of the dot.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 933-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single GaN/AlGaN Quantum Dot Spectroscopy
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047382.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Microphotoluminescence of low-density GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N quantum dots grown by metal-organic vapor phase epitaxy using in situ etching of AlGaN is presented. The detailed analysis of the emission from these structures enables the observation of pairs of lines separated by the energy up to 3 meV. They behave in a different way under different excitation power that suggests that this doublet structure can be associated with the exciton and trion (or biexciton recombination). It is observed that for different quantum dots the energy of the charged exciton complex emission could be higher or lower than the neutral exciton one. It is discussed in terms of a competition between attractive e-h and repulsive e-e (h-h) Coulomb interaction that occurs because of the existence of the built-in electric field that separates electrons and holes in the dot.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 233-236
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temporal Evolution of Multi-Carrier Complexes in Single GaN/AlGaN Quantum Dots
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2044542.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Microphotoluminescence of low-density GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N quantum dots grown by metal-organic vapor phase epitaxy using in situ etching of AlGaN is presented. The narrow lines in the microphotoluminescence spectra due to the single quantum dots are observed. Both energy and intensity of these lines show temporal fluctuations. Statistical analysis based on the correlation matrix allowed us to identify objects, which are affected by photo-induced electric field fluctuations. Relations between emission lines participating in the spectrum are discussed.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 879-884
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
GaSb Dots Grown on GaAs Surface by Metalorganic Chemical Vapour Deposition
Autorzy:
Bożek, R.
Babiński, A.
Baranowski, J. M.
Stępniewski, R.
Klusek, Z.
Olejniczak, W.
Starowieyski, K.
Wróbel, J.
Powiązania:
https://bibliotekanauki.pl/articles/1934054.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
68.55.-a
Opis:
We report metaloorganic chemical vapour deposition growth of an anisotropic GaSb islands on GaAs (001) surface with a typical dimensions around 200 nm. Results of investigations employing scanning electron microscope, scanning tunnelling microscope and ph9tocapacitance are presented.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 974-976
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Absorption and Raman Scattering Studies of Few-Layer Epitaxial Graphene Grown on 4H-SiC Substrates
Autorzy:
Grodecki, K.
Drabińska, A.
Bożek, R.
Wysmołek, A.
Korona, K.
Strupiński, W.
Borysiuk, J.
Stępniewski, R.
Baranowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791292.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Tr
78.40.Ri
78.30.Na
63.20.dd
63.20.kd
Opis:
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.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 835-837
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphene Based Flow Sensors
Autorzy:
Kaźmierczak, P.
Binder, J.
Boryczko, K.
Ciuk, T.
Strupiński, W.
Stępniewski, R.
Wysmołek, A.
Powiązania:
https://bibliotekanauki.pl/articles/1195452.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.65.Pq
72.80.Vp
73.30.+y
Opis:
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.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1209-1211
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magneto-Luminescence Study of Silicon-Vacancy in 6HSi
Autorzy:
Wysmołek, A.
Wardak, K.
Stępniewski, R.
Baranowski, J.
Potemski, M.
Tymicki, E.
Grasza, K.
Powiązania:
https://bibliotekanauki.pl/articles/2047066.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
71.55.-i
71.55.Ht
Opis:
The magneto-spectroscopy studies of luminescence related to silicon-vacancy, in high quality 6H-SiC crystals grown by the seeded physical vapor transport method, are presented. The superior optical quality of these crystals allowed us to resolve a doublet structure of the 1.398 eV emission line (V$\text{}_{2}$ line), commonly assigned to the transitions involving two singlet states of the silicon-vacancy. Experiments performed in magnetic fields up to 20 T showed that each doublet constituent of the V$\text{}_{2}$ line splits into four components for the magnetic field parallel to the c-axis of the 6H-SiC crystals. This result could be hardly explained in terms of a singlet to singlet transition. The analysis of the angle-resolved luminescence experiments in high magnetic fields serves us to discuss the symmetry of the defect states responsible for the V$\text{}_{2}$-line in silicon carbide.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 437-442
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Piezospectroscopy of Phonons in Bulk 6H-SiC
Autorzy:
Grodecki, K.
Wysmołek, A.
Stępniewski, R.
Baranowski, J.
Hofman, W.
Tymicki, E.
Grasza, K.
Powiązania:
https://bibliotekanauki.pl/articles/1791360.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.50.-p
42.65.Dr
63.20.-e
78.30.-j
Opis:
Raman piezospectroscopy of high quality 6H-SiC crystals is presented. The crystals used in experiments were grown by the seeded physical vapor transport method. Uniaxial stress up to 0.9 MPa, obtained using a spring apparatus, was applied along [11-20] and [10-10] directions. It was found that the application of uniaxial stress led to different energy shifts of the observed phonon excitations in the investigated 6H-SiC crystals. The obtained pressure coefficients vary in the range 0.98-5.5 $cm^{-1}$ $GPa^{-1}$ for different transverse optical phonon modes. For longitudinal optic phonon modes pressure coefficients in the range 1.6-3.6 $cm^{-1}$ $GPa^{-1}$ were found. The data obtained could be useful in evaluation of local strain fields in SiC based structures and devices including epitaxial graphene.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 947-949
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth of GaN Metalorganic Chemical Vapour Deposition Layers on GaN Single Crystals
Autorzy:
Pakula, K.
Baranowski, J. M.
Stępniewski, R.
Wysmołek, A.
Grzegory, I.
Jun, J.
Porowski, S.
Sawicki, M.
Starowieyski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1933937.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
78.55.Cr
Opis:
The homoepitaxial growth of GaN layers has been achieved for the first time. Bulk GaN single crystals which have been used as a substrate have been grown from diluted solution of atomic nitrogen in the liquid gallium at 1600°C and at nitrogen pressure of about 15-20 kbar. It is shown that a terrace growth of GaN epitaxial layer has been realized. The high quality of the GaN film has been confirmed by luminescence measurements. The analysis of donor-acceptor and exciton luminescence is presented.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 861-864
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatially Resolved Micro-Luminescence from GaN/AlGaN Quantum Dots
Autorzy:
Chwalisz, B.
Wysmołek, A.
Bożek, R.
Stępniewski, R.
Pakuła, K.
Kossacki, P.
Golnik, A.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2038084.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.66.Fd
78.67.Hc
75.75.+a
68.65.Hb
Opis:
We report on the optical experiments performed on low density GaN/AlGaN quantum dots grown on sapphire substrate using SiN during the growth process. The existence of quantum dots in the investigated structures was confirmed by atomic force microscopy. Although macro-luminescence of the investigated structures consist of broad emission lines the micro-photoluminescence experiments performed with the spatial resolution of 0.25 μm revealed sharp emission lines from the individual quantum dot in the energy range of 3.20-3.55 eV. It is shown that the magnetic fields up to 7 T do not influence significantly the electronic states of the dots.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 517-521
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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