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    Wyświetlanie 1-48 z 48
    Tytuł:
    Magnetized Plasma in Polar Semiconductors
    Autorzy:
    Wysmołek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047367.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.30.Fs
    73.20.Mf
    78.20.Ls
    Opis:
    Plasma excitations in metallic n-type GaAs are studied in high-magnetic fields using the method of inelastic light scattering (the Raman scattering). Experimental data are analyzed using a standard, dielectric function theory. The results obtained for samples with a high electron concentration are well understood in terms of longitudinal excitations. A strong interaction of coupled longitudinal optical-phonon-plasmon modes with the collective cyclotron resonance excitations (the Bernstein modes) is observed. In samples with a lower electron concentration, the unexpected feature in the vicinity of the undressed optical phonon is observed at high magnetic fields. This effect is explained in terms of transverse excitations, which would appear in the Raman spectrum due to disorder-activated selection-rule breaking. A field induced metal-insulator transition and magnetopolaron effect on shallow donors in GaAs is shown to be traced with the Raman scattering experiments in samples with the lowest electron concentration.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 141-152
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Orientation of Metastable EL2 under Uniaxial Stress
    Autorzy:
    Babiński, A.
    Wysmołek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1931913.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    72.20.Fr
    72.80.Ey
    Opis:
    Results of electrical resistivity and Hall measurements of n-type GaAs under uniaxial stress along [111] direction performed at low temperature are presented. Alter the transformation of the EL2 defect into its metastable configuration, a stress-induced increase in electrical resistivity related to the capture of electrons by the acceptor state of the metastable EL2([EL2*]$\text{}_{-}\text{}_{/}\text{}_{0}$) was observed. It was found that the stress-induced increase in resistivity depended on the method of EL2-photoquenching. The observed effects are explained as the reorientation of EL2* centers in the crystal. The stress coefficients of the triple degenerate and the single degenerate sublevels of the [EL2*]$\text{}_{-}\text{}_{/}\text{}_{0}$ are found to be equal to -17 meV/GPa and -41 meV/GPa.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 137-140
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electrical Properties of an Acceptor-like State of Metastable EL2 in n-type GaAs under Uniaxial Stress
    Autorzy:
    Babiński, A.
    Wysmołek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1924252.pdf
    Data publikacji:
    1992-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    72.20.Fr
    72.80.Ey
    Opis:
    The electrical resistivity and deep level transient spectroscopy measurements of n-type GaAs under uniaxial stress for [100] and [111] directions at low temperatures are presented. After the transformation of EL2 to its metastable state the stress induced strong anisotropy in the increase in resistivity was observed. The observed splitting of the acceptor-like state of metastable EL2 implies the trigonal symmetry of that defect.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 5; 908-910
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Impact Ionization of Shallow Donors on Luminescence in GaAs
    Autorzy:
    Wysmołek, A.
    Łusakowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1932094.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.-m
    72.20.Ht
    Opis:
    Luminescence spectra of n-type molecular beam epitaxial layer and semi-insulating liquid encapsulated Czochralski grown bulk GaAs were measured at liquid helium temperature for zero electric field and for fields which caused impact ionization of shallow donors. Application of the electric field caused a decrease in the luminescence intensity and a broadening of all observed structures. It was found that the electric field changed the luminescence spectrum of the n-type material in a different way than it did in the case of the semi-insulating one. For the n-type sample, an intensity of excitonic lines decreased much more than that of donor-acceptor lines when the electric field grew. A contrary was observed for the semi-insulating sample. An explanation of the result is proposed which takes into account an influence of ionised impurity scattering and localization in fluctuations of the electrostatic potential on the luminescence process.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 261-264
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Shallow Donors and Acceptors in GaN; Bound Excitons and Pair Spectra
    Autorzy:
    Stępniewski, R.
    Wysmołek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1946873.pdf
    Data publikacji:
    1996-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.-y
    71.55.Eq
    71.38.+i
    Opis:
    Recent photoluminescence results obtained for homoepitaxial GaN layers are presented. Dominant photoluminescence structures observed for these layers can be assigned to excitons bound to neutral impurities. Different methods such as temperature dependent evolution, high magnetic field and time resolved spectroscopy have been used to study the exciton line properties. For the p-type samples sharp lines are observed, assigned to the donor-acceptor recombination for differently distant pairs. The analysis of the optical transitions related to donors and acceptors is in reasonable agreement with the effective mass approximation. Electron phonon interaction was found to strongly affect the optical properties of GaN. The dominant intrinsic defect has been identified as a donor located at a nitrogen site.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 4; 681-690
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deep Level Transient Spectroscopy Measurements of an Acceptor-like State of Metastable EL2 in GaAs and GaAsP
    Autorzy:
    Babiński, A.
    Wysmołek, A.
    Słupiński, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1929708.pdf
    Data publikacji:
    1993-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    Opis:
    The results of deep level transient spectroscopy measurements of an acceptor-like state of metastable EL2 in GaAs and GaAs$\text{}_{0.97}$P$\text{}_{0.03}$ are presented. The uniaxial stress in GaAs was applied in order to find the deep leve1 transient spectroscopy signal. It was found that the deep level transient spectroscopy signal depended on the stress direction. In GaAs$\text{}_{0.97}$P$\text{}_{0.03}$ the deep level transient spectroscopy peak related to an acceptor-like state of metastable EL2 was observed without external stress.
    Źródło:
    Acta Physica Polonica A; 1993, 84, 4; 673-676
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Origin of Centres Involved in Blue and Orange Luminescence of 6H-SiC
    Autorzy:
    Wysmołek, A.
    Baranowski, J. M.
    Kamińska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934050.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.-m
    78.20.-e
    78.60.Kn
    Opis:
    We present new results of luminescence of n-type 6H-SiC crystals. We have found two shallow donors with ionization energies at 60 meV and 140 meV. We have shown that the blue luminescence is not affected by the ionization of the shallower donor and is related to deeper donor which we attribute to N at C-site. We propose that the origin of the more shallower donor at 60 meV is related to carbon vacancy. We have found that the intensity of the orange luminescence increases under infrared illumination. This result confirms that the orange luminescence is due to conduction band-deep centre transitions. We believe that deep centre responsible for the orange luminescence is the silicon vacancy.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 957-960
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    "Excitonic" and Photoionization Absorption Spectra of Iron in III-V Materials
    Autorzy:
    Wysmołek, A.
    Tryc, R.
    Bożek, R.
    Hennel, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1924253.pdf
    Data publikacji:
    1992-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    78.55.Cr
    Opis:
    We report optical absorption measurements of Fe-doped GaAs, InP and GaP crystals obtained with the help of different doping techniques. In all these crystals photoionization spectra corresponding to Fe$\text{}^{3+}$ → Fe$\text{}^{2+}$ transitions with sharp "excitonic" lines were observed. The intensities of these lines are not proportional to the intensities of photoionization absorption bands, i.e. to the concentration of the Fe$\text{}^{3+}$ centers. Variation of more than one order of magnitude was observed for different semiconductors and for different crystals of the same material. These results suggest that only some iron centers are responsible for the "excitonic" spectra.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 5; 911-913
    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:
    Hydrostatic Pressure Spectroscopy of the Vanadium Luminescence in GaAs
    Autorzy:
    Wysmołek, A.
    Bożek, R.
    Babiński, A.
    Hennel, A. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1923845.pdf
    Data publikacji:
    1992-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    78.55.Cr
    Opis:
    We report luminescence measurements of the intracenter transition $\text{}^{3}$T$\text{}_{2}$ → $\text{}^{3}$A$\text{}_{2}$ of the V$\text{}^{3+}$(3d$\text{}^{2}$) charge state in semi-insulating GaAs under hydrostatic pressure up to 0.8 GPa at liquid helium temperature. The hydrostatic pressure coefficient of the zero-phonon line is found to be equal to 6.9 ± 0.2 meV/GPa. This result enables us to determine the Huang-Rhys parameter, which characterizes the coupling to the symmetric mode of vibration, as S$\text{}_{A}$ = 1.4 ± 0.1. Using this parameter, computer simulation leading to a reconstruction of the shape of both luminescence and corresponding absorption spectra were performed.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 5; 837-840
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time Resolved Magnetophotoluminescence of Biased GaAs/AlGaAs Double Quantum Well Structure
    Autorzy:
    Surowiecka, K.
    Wysmołek, A.
    Stępniewski, R.
    Potemski, M.
    Henini, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811991.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.Ji
    78.67.De
    Opis:
    Time resolved photoluminescence of double quantum well structure was investigated versus electric and magnetic fields applied across the sample. The emission due to direct excitons (electron and hole are localized within the same quantum well) decays fast at the nanosecond timescale, whereas the recombination kinetics of indirect excitons is much slower and spreads over microseconds. The time evolution of indirect exciton emission is shown to be altered by application of either electric or magnetic field. This reflects the non-trivial effects of exciton localization which leads to the non-exponential decays of the indirect exciton emission.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1369-1374
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Competition of Radiation Processes in 6H-SiC Observed by Luminescence
    Autorzy:
    Wysmołek, A.
    Mroziński, P.
    Dwiliński, R.
    Vlaskina, S.
    Kamińska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1873137.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.-m
    78.60.Kn
    Opis:
    We report on the results of photoluminescence and thermoluminescence measurements of various 6H-SiC crystals. At low temperature in all n-type samples two bands with maxima at 2.7 eV (blue) and 1.8 eV (orange) were detected. In the p-type material only blue band was observed. The measurements performed at a broad range of temperatures showed totally different behaviour of photoluminescence intensity of both bands. The presented results could be explained in the model assuming well established donor-acceptor pair recombination for the blue band emission and the conduction band - deep defect transition for the orange band. The proposed model was confirmed by thermoluminescence measurements of the orange band which showed peaks at 30 K, 80 K, 100 K, 150 K attributed to ionization of subsequent shallow donor levels.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 437-440
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmission Electron Microscopy and Luminescence Studies of Quantum Well Structures Resulting from Stacking Fault Formation in 4H-SiC Layers
    Autorzy:
    Borysiuk, J.
    Wysmołek, A.
    Bożek, R.
    Strupiński, W.
    Baranowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811916.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.37.Lp
    78.55.-m
    61.72.Nn
    68.65.Fg
    61.72.up
    Opis:
    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.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1067-1072
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Strong Photoluminescence Fluctuations in Laser-Thinned Few-Layer WS₂
    Autorzy:
    Bala, Ł.
    Łacińska, E.
    Nogajewski, K.
    Molas, M.
    Wysmołek, A.
    Potemski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398573.pdf
    Data publikacji:
    2016-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.22.-f
    71.35.-y
    78.55.-m
    78.30.-j
    Opis:
    We present results of μ-Raman and μ-photoluminescence study of few-layer WS₂ flakes that have been locally thinned down by a focused laser beam. The Raman spectroscopy measurements prove that the investigated flake was locally thinned down to a monolayer. Interestingly, μ-photoluminescence experiments allowed us to observe huge intensity fluctuations at the boundary of laser-thinned region. Similar effects were found at the edges of a WS₂ bilayer flake, which has not been subjected to laser-thinning. The origin of the observed time evolution of the photoluminescence response is discussed in terms of potential fluctuations resulting from light-induced changes of the charge state of defects.
    Źródło:
    Acta Physica Polonica A; 2016, 130, 5; 1176-1178
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Built-In Electric Field in High Quality GaN/AlGaN Quantum Wells
    Autorzy:
    Zieleniewski, K.
    Pakuła, K.
    Bożek, R.
    Masztalerz, K.
    Wysmołek, A.
    Stępniewski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/2048083.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    78.67.De
    77.55.hn
    81.15.Gh
    Opis:
    We report studies on electric field built in GaN/Al$\text{}_{0.09}$Ga$\text{}_{0.91}$N structure of nominally 6 nm wide quantum well. The sample was grown in horizontal metal-organic chemical vapor deposition reactor using innovative technology that decreases the density of screw dislocations. Firstly, using visible and mid infra-red interference pattern along the sample, the layer thickness and consequently the quantum well width was determined to vary linearly with the position. Secondly, photoluminescence spectra was taken at different positions. Correlation of those two measurements allows us to determine the built-in electric field to be 0.66 MV/cm, which is considerably larger than previously reported for similar structures.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 657-659
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoluminescence Study of Bulk GaN Doped with Beryllium
    Autorzy:
    Jaworek, M.
    Wysmołek, A.
    Kamińska, M.
    Twardowski, A.
    Boćkowski, M.
    Grzegory, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/2043722.pdf
    Data publikacji:
    2005-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    71.55.-i
    71.35.-y
    Opis:
    Photoluminescence of bulk GaN:Be grown by high pressure method is presented. The investigated crystals show well-resolved photoluminescence due to free and bound excitons similar to that observed for homoeptitaxial GaN layers. In addition to the excitonic transitions, pronounced luminescence band at 3.38 eV, due to Be acceptor, is observed. It was found that temperature behavior of this emission is typical of donor- and conduction band-acceptor transitions. The optical activation energy of Be acceptor is obtained to be of 60±15 meV.
    Źródło:
    Acta Physica Polonica A; 2005, 108, 4; 705-710
    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:
    Carriers Diffusion in GaAs/AlAs Type II Quantum Well
    Autorzy:
    Lesiak, A.
    Chwalisz, B.
    Wysmołek, A.
    Potemski, M.
    Stępniewski, R.
    Thierry-Mieg, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/2044497.pdf
    Data publikacji:
    2005-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    78.66.Fd
    78.67.Hc
    75.75.+a
    Opis:
    The micro-photoluminescence of GaAs/AlAs type II double quantum well structure is presented. The specific band alignment of the investigated system allows obtaining high concentration of long lived carriers. This enables us to study diffusion of carriers and/or indirect excitons. It was found that the carrier flow does not follow the classical diffusion equation and is driven by the potential modification due to the presence of photo created carriers.
    Źródło:
    Acta Physica Polonica A; 2005, 108, 5; 755-760
    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:
    Raman spectroscopy of shear modes in a few-layer MoS₂
    Autorzy:
    Gołasa, K.
    Grzeszczyk, M.
    Zinkiewicz, M.
    Nogajewski, K.
    Potemski, M.
    Wysmołek, A.
    Babiński, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1160654.pdf
    Data publikacji:
    2016-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.-e
    87.64.Je
    63.20.Kr
    Opis:
    We study low frequency vibrational modes in atomically thin molybdenum disulfide (MoS₂) by means of the Raman scattering spectroscopy. A shear mode related to rigid interlayer vibrations is identified. Its energy evolution with the increasing number of layers is well described using a linear chain model with only nearest neighbor interactions. The resulting force constant (Kₓ = 2.7 × 10¹⁹ N/m³) corresponds well to the previously published data.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 1a; A-132-A-134
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Light Induced Modification of Graphene Oxide Layers on GaN Basis
    Autorzy:
    Łopion, A.
    Stobiński, L.
    Pakuła, K.
    Bożek, R.
    Kaźmierczak, P.
    Wysmołek, A.
    Stępniewski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1185429.pdf
    Data publikacji:
    2016-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.22.-f
    78.55.-m
    78.30.-j
    07.05.Kf
    Opis:
    Graphene oxide suspension in various solvents was spin coated on metal organic vapor phase epitaxy grown GaN/saphire layers. Samples were characterised using the Raman spectroscopy and atomic force microscopy, before and after high temperature treatment. We found that graphene oxide was modifed by high temperature treatment, however a considerable modification was also observed as a result of impinged laser light incident due to the measurements. The Raman spectra were decomposed into two contributions showing different behaviour during the Raman scattering measurements.
    Źródło:
    Acta Physica Polonica A; 2016, 130, 5; 1169-1171
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    ESR Spectroscopy of Graphene with Adsorbed NaCl Particles
    Autorzy:
    Karpierz, E.
    Drabińska, A.
    Bożek, R.
    Kaźmierczak, P.
    Wysmołek, A
    Kamińska, M
    Strupiński, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1376214.pdf
    Data publikacji:
    2014-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.ue
    72.10.Fk
    78.67.Wj
    72.80.Vp
    Opis:
    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).
    Źródło:
    Acta Physica Polonica A; 2014, 126, 5; 1187-1189
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time-Resolved Studies of Gallium Nitride Doped with Gadolinium
    Autorzy:
    Witek, B.
    Wysmołek, A.
    Kamińska, M.
    Twardowski, A.
    Potemski, M.
    Boćkowski, M.
    Grzegory, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812021.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    75.50.Pp
    71.55.-i
    71.35.Ji
    Opis:
    Time-resolved photoluminescence experiments on high quality bulk GaN doped with Gd are presented. It was found that the decay time of Gd-related transitions observed for 4.2 K around 1.78 eV is of about 3 ms. Such a long decay time strongly supports the identification of this emission band as due to transitions between Gd³+(4f⁷) levels. The decay time measured for Gd-related transitions observed in the UV spectral range, close to the GaN band-gap, was found to be much faster than 1 μs. This suggests that these emission lines could hardly be correlated with internal transitions within Gd³+(4f⁷). Possible origin of the Gd-related UV luminescence is discussed.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1425-1430
    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:
    Absorption and Emission Properties of Light Emitting Diode Structures Containing GaInN/GaN QWs
    Autorzy:
    Binder, J.
    Korona, K.
    Borysiuk, J.
    Wysmołek, A.
    Baeumler, M.
    Köhler, K.
    Kirste, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492933.pdf
    Data publikacji:
    2011-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    72.40.+w
    73.61.Ey
    Opis:
    In this work we present measurements of GaInN/GaN light emitting diodes (LEDs) with an active layer consisting of three quantum wells made of $Ga_{0.9}In_{0.10}N$ that have different widths (1.8 nm, 2.7 nm, 3.7 nm). A comparison of emission and absorption (photocurrent) on the same sample revealed a shift in energy, with the emission energy being significantly lower. The shifts are about 0.02 eV, 0.03 eV, and 0.04 eV for the quantum wells having the widths of 1.8 nm, 2.7 nm, and 3.7 nm, respectively. This can be explained by a shift of the ground state energy caused by the quantum confined Stark effect. Calculations show that due to the spontaneous polarization and the piezoelectric effect a strong electric field of the order of 1 MV/cm was present in the GaInN quantum wells. Simulations of ground-state energies in the model of an infinite square well under the influence of an electric field with a matched effective well width were performed and used to interpret the experimental results.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 5; 918-920
    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:
    Optical and Electrical Studies of FR1 and FR2 Defects in GaAs
    Autorzy:
    Dwiliński, R.
    Palczewska, M.
    Kaczor, P.
    Korona, K.
    Wysmołek, A.
    Bożek, R.
    Kamińska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1920972.pdf
    Data publikacji:
    1992-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.-i
    78.50.Ge
    76.30.Mi
    Opis:
    The systematic EPR, optical absorption, photoluminescence and thermally stimulated current studies of acceptor defects in bulk GaAs were performed. For the first time, parallel EPR and optical absorption experiments allowed to find the absorption spectrum due to the photoionization of FR1 defect with the threshold at 0.19 eV. Photoluminescence studies showed two families of bands in the energy range of about 1.25 to 1.35 eV. We tentatively ascribed them to FR1 and FR2 complexes with shallow donors. Thermally stimulated current measurements showed two peaks at 90 K and 110 K assigned to FR1 and FR2 respectively.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 4; 613-616
    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:
    Two-Electron Transition in Homoepitaxial GaN Layers
    Autorzy:
    Fiorek, A.
    Baranowski, J. M.
    Wysmołek, A.
    Pakuła, K.
    Wojdak, M.
    Grzegory, I.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968067.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.66.Fd
    78.55.Cr
    Opis:
    It is shown that the luminescence mapping is a powerful method to help identify optical transitions. Two-electron transition was identified in the homoepitaxial GaN layer by this technique. It was found that the donor and acceptor bound exciton emissions are spatially displaced and show intensity maxima at different places of the epitaxial layer. It was also found that the 3.45 eV line, suspected as "two-electron transition", follows exactly the donor bound exciton spatial distribution. Donor bound exciton recombines leaving the neutral donor in the excited 2s state. Thus, 1s-2s excitation being equal to 22 meV corresponds to 29 meV hydrogenic donor binding energy. This is the first identification of the two-electron transition in GaN.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 742-744
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Emission from Mesoscopic-Size Islands Formed in a GaAs/AlAs Double Layer Structure
    Autorzy:
    Wysmołek, A.
    Chwalisz, B.
    Potemski, M.
    Stępniewski, R.
    Babiński, A.
    Raymond, S.
    Thierry-Mieg, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/2038338.pdf
    Data publikacji:
    2004-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.De
    78.20.Ls
    71.35.Lk
    73.20.-r
    78.47.+p
    Opis:
    The nature of sharp emission lines which are present in macro-luminescence experiments on a type-II GaAs/AlAs double quantum well structure is discussed. The experiments, which also include micro-lumines- cence measurements, allowed us to conclude that the sharp emission lines observed originate from lateral GaAlAs islands of a fewμm in diameter. They serve as efficient type-I recombination centers for indirect excitons and/or carriers which diffuse in the GaAs/AlAs QW structure and strongly affect the emission processes observed in macro-luminescence experiments. These traps can easily be filled with electron-hole pairs, giving rise to the formation of neutral excitons as well as more complex excitonic molecules. Magneto-luminescence spectra from single islands resemble those observed for natural quantum dots formed in narrow GaAs quantum wells.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 3; 367-381
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical and Electrical Measurements of Low-Temperature InAlAs
    Autorzy:
    Korona, K. P.
    Wysmołek, A.
    Bożek, R.
    Kamińska, M.
    Baranowski, J. M.
    Weber, E. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1923833.pdf
    Data publikacji:
    1992-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    73.60.Br
    78.55.Cr
    Opis:
    Photoluminescence, photocurrent, thermally stimulated current and photoinduced current transient spectroscopy measurements done on molecular beam epitaxy In$\text{}_{0.52}$Al$\text{}_{0.48}$As layer, lattice matched to InP are reported. The investigated layers were grown on semi-insulating InP wafers, at temperature range from 215 to 450°C. It was found that the Fermi level was pinned to a dominant midgap center (most likely similar to EL2 center). Moreover, there were at least 7 other defects but with much smaller concentrations. Their activation energies were equal to 0.076, 0.11, 0.185, 0.295, 0.32 and 0.40 eV. The layers exhibited a very low luminescence and a small photocurrent.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 5; 825-828
    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:
    Anharmonic Optical Phonon Effects in ZnO Nanocrystals
    Autorzy:
    Khusnutdinov, S. V.
    Dynowska, E.
    Zaleszczyk, W.
    Makhniy, V. P.
    Wysmołek, A.
    Korona, K. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2048106.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.61.Ga
    74.25.nd
    63.20.kg
    Opis:
    Zinc oxide (ZnO) is a very promising material for optoelectrical devices operating at the short-wavelength end of the visible spectral range and at the near UV. The Raman scattering studies of ZnO heterolayers formed by isothermal annealing show sharp phonon lines. In addition to the A$\text{}_{1}$(TO), E$\text{}_{1}$(TO), E$\text{}_{2}^{H}$, and E$\text{}_{1}$(LO) one-phonon lines, we observed two-phonon lines identified as: E$\text{}_{2}^{H}$ - E$\text{}_{2}^{L}$, E$\text{}_{2}^{H}$ + E$\text{}_{2}^{L}$, and 2LO at 332, 541, and 1160 cm$\text{}^{-1}$, respectively (at room temperature). The identification of the E$\text{}_{2}^{H}$ - E$\text{}_{2}^{L}$ peak was confirmed by its thermal dependence. Temperature dependent measurements in the range 6-300 K show that the phonon frequencies decrease with temperature. The E$\text{}_{2}^{H}$ peak is at energy 54.44 meV (439.1 cm$\text{}^{-1}$), at 4 K and due to phonon-phonon anharmonic interaction, its energy decreases to 54.33 meV (438.2 cm$\text{}^{-1}$) at room temperature. The Grüneisen parameter found for this oscillation mode was γ$\text{}_{E}$ 2H = 1.1 at about 300 K. The intensity of the E$\text{}_{2}^{H}$ - E$\text{}_{2}^{L}$ peak increases strongly with temperature and this dependence can be described by the Bose-Einstein statistics with activation energy of 13.8 meV (nearly equal to the energy of the E$\text{}_{2}^{L}$ phonon).
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 678-680
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical Properties of Molybdenum Disulfide $(MoS_2)$
    Autorzy:
    Gołasa, K.
    Grzeszczyk, M.
    Korona, K.
    Bożek, R.
    Binder, J.
    Szczytko, J.
    Wysmołek, A.
    Babiński, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399110.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    63.22.-m
    71.35.-y
    78.20.-e
    78.30.-j
    Opis:
    Research of a monolayer and a bulk $MoS_2$ is reported. The room temperature Raman spectra of the natural $MoS_2$ crystals for the both resonant (632.8 nm) and the non-resonant (532 nm) excitation are presented. The apparent differences observed in the spectra from the bulk and the one monolayer $MoS_2$ are discussed. In particular, the feature due to a first order scattering involving the LA(M) phonon in the resonance Raman spectrum of the one monolayer $MoS_2$ was observed and explained in terms of the disorder in the natural crystal. The disorder is also documented by the line-shape of the room-temperature photoluminescence spectra observed from both the bulk and the one monolayer $MoS_2$.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 849-851
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    GaN Synthesis by Ammonothermal Method
    Autorzy:
    Dwiliński, R.
    Wysmołek, A.
    Baranowski, J.
    Kamińska, M.
    Doradziński, R.
    Garczyński, J.
    Sierzputowski, L.
    Jacobs, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933907.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.10.Dn
    Opis:
    It is shown that ammonothermal method can be successfully used to synthesize GaN powder of good crystallographic quality from ammonia solution at high pressure and a moderate temperature. The size of obtained GaN powder grains was of a few micrometers. The improvement of the powder crystalline quality (examined by X-ray rocking curve, scanning electron microscopy and luminescence measurements) with increasing molar proportion of mineralizer was observed. It was therefore possible to conclude that high molar proportion of mineralizer in ammonia solution plays a crucial role in the polycrystal growth process. Visible luminescence of high efficiency from the GaN powder was found.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 833-836
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    GaN Layers Grown by Reactive Ion Plating
    Autorzy:
    Żubka, A.
    Dwiliński, R.
    Suchanek, B.
    Janik, W.
    Wysmołek, A.
    Kwiatkowski, S.
    Kamińska, M.
    Shaginyan, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1943889.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.15.Jj
    68.55.Gi
    Opis:
    GaN layers grown on ceramics, sapphire or SiC substrates using reactive ion plating method are presented. In reactive ion plating method gallium from a hot source reacts on a heated substrate with nitrogen partially ionized. Rutherford backscattering technique was applied to check the composition of the samples and gallium to nitrogen ratio was found to be close to one. However, Rutherford backscattering studies showed also a remarkable amount of unintentional impurities present in the layers. The structure of GaN was determined using reflection high-energy electron diffraction. It appeared that polycrystal and monocrystal can be grown, depending on growth conditions. Absorption spectra taken on the layers grown on sapphire showed a tail of band to band absorption starting at about 370 nm. Carrier concentration was of the order of 1019-1020 cm$\text{}^{-3}$ at room temperature and did not change much with temperature decrease. No luminescence from the layers was detected, most probably due to high concentration of impurities.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 1058-1062
    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
    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:
    Structural and optical properties of boron nitride grown by MOVPE
    Autorzy:
    Dąbrowska, A.
    Pakuła, K.
    Bożek, R.
    Rousset, J.
    Ziółkowska, D.
    Gołasa, K.
    Korona, K.
    Wysmołek, A.
    Stępniewski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1160531.pdf
    Data publikacji:
    2016-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.15.Gh
    78.30.Fs
    78.20.-e
    Opis:
    Boron nitride layers were grown on sapphire substrate by metal organic vapor phase epitaxy system that was originally designed for growth of GaN. Structures were characterized by scanning electron microscopy, atomic force microscopy, the Raman spectroscopy, absorption and time resolved photoluminescence. Presented results confirm successful deposition of BN layers and gives information about basic properties of the material. The Raman line at 1370 cm^{-1} and absorption edges at 5.6-5.9 eV were observed which is related to hexagonal phase.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 1a; A-129-A-131
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoluminescence and Electron Paramagnetic Resonance Studies of Bulk GaN Doped with Gadolinium
    Autorzy:
    Lipińska, Z.
    Pawłowski, M.
    Żołnierowicz, H.
    Wysmołek, A.
    Palczewska, M.
    Kamińska, M.
    Twardowski, A.
    Boćkowski, M.
    Grzegory, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046930.pdf
    Data publikacji:
    2006-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    71.55.-i
    71.35.-y
    Opis:
    Photoluminescence and electron paramagnetic resonance experiments on strain free GaN bulk crystals of wurtzite structure doped with gadolinium are reported. Efficient gettering of residual GaN donors by Gd was observed. Electron paramagnetic resonance showed that Gd ion incorporated into GaN lattice had Gd$\text{}^{3+}$(4f$\text{}^{7}$) configuration. The observed photoluminescence spectra were explained as due to intracenter Gd$\text{}^{3+}$(4f$\text{}^{7}$) transitions. No ferromagnetic behavior was detected.
    Źródło:
    Acta Physica Polonica A; 2006, 110, 2; 243-248
    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:
    Magnetoluminescence Studies of GaN:Fe
    Autorzy:
    Niedźwiadek, A.
    Wysmołek, A.
    Wasik, D.
    Potemski, M.
    Szczytko, J.
    Kamińska, M.
    Twardowski, A.
    Łucznik, B.
    Pastuszka, B.
    Grzegory, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047373.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Et
    71.55.Eq
    71.20.Be
    Opis:
    We report on magneto-optical studies on iron doped GaN crystals grown using hydride vapor phase epitaxy method on bulk GaN substrate. The investigated samples showed an intensive 1.3 eV luminescence band, characteristic of Fe$\text{}^{3+}$(d$\text{}^{5}$) center in GaN. A high quality of the investigated samples allowed us to observe a well-resolved fine structure of intracenter transitions between $\text{}^{4}$T$\text{}_{1}$(G) and $\text{}^{6}$A$\text{}_{1}$(S) states, consisting of four sharp no-phonon lines. All the observed no-phonon lines showed pronounced splittings in magnetic field. From the analysis of the magneto-optical data, the structure of split $\text{}^{4}$T$\text{}_{1}$(G) multiplet in the magnetic field applied along c-axis of GaN crystals was established.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 177-182
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical and Electrical Studies of Graphene Deposited on GaN Nanowires
    Autorzy:
    Kierdaszuk, J.
    Kaźmierczak, P.
    Drabińska, A.
    Wysmołek, A.
    Korona, K.
    Kamińska, M.
    Pakuła, K.
    Pasternak, I.
    Krajewska, A.
    Żytkiewicz, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1195433.pdf
    Data publikacji:
    2014-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.ue
    72.10.Fk
    78.67.Wj
    72.80.Vp
    Opis:
    In this paper using scanning electron microscope, contactless microwave electronic transport and the Raman spectroscopy we studied the properties of graphene deposited on GaN nanowires and compared it with the graphene deposited on GaN epilayer. The Raman micro-mapping showed that nanowires locally change the strain and the concentration of carriers in graphene. Additionally we observed that nanowires increase the intensity of the Raman spectra by more than one order of magnitude.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 5; 1087-1089
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Coupling of LO Phonons to Excitons in GaN
    Autorzy:
    Wysmołek, A.
    Łomiak, P.
    Baranowski, J. M.
    Pakuła, K.
    Stępniewski, R.
    Korona, K. P.
    Grzegory, I.
    Boćkowski, M.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952430.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    63.20.Mt
    71.55.Eq
    Opis:
    The photoluminescence of homoepitaxial and heteroepitaxial GaN layers is reported. It is shown that the coupling between LO phonons and neutral acceptor bound excitons is much stronger than the coupling between LO phonons and neutral donor bound excitons. In undoped homoepitaxial layer, in spite of that the no-phonon emission due to donor bound excitons is one order of magnitude stronger than the acceptor bound excitons emission, the predominant structure in the LO phonon replica of the excitonic spectrum is related to optical transitions involving acceptor bound excitons. Temperature studies showed that at higher temperature the LO phonon replica is related to free excitons.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 981-984
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Formation of Mn-Related Defect Band in InP
    Autorzy:
    Macieja, B.
    Korona, K. P.
    Piersa, M.
    Witowski, A. M.
    Wasik, D.
    Wysmołek, A.
    Strzelecka, G.
    Hruban, A.
    Surma, B.
    Palczewska, M.
    Kamińska, M.
    Twardowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2036033.pdf
    Data publikacji:
    2003-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    72.20.Ee
    72.20.Jv
    Opis:
    Electron paramagnetic resonance, optical absorption, luminescence and electrical studies of InP highly doped with Mn were performed. Electron paramagnetic resonance revealed presence of manganese in Mn$\text{}^{2+}$(d$\text{}^{5}$) configuration. In optical absorption, systematic reduction of InP band gap was observed with increase in Mn content. This was correlated with increase in photoionization-type absorption band starting at 0.2 eV. Time-resolved photoluminescence measurements showed decrease in photoexcited carrier lifetime and shortening of donor-acceptor pair recombination time with increase in Mn content. Moreover, photoluminescence band was shifted to lower energies, similarly to optical band gap. In electrical transport two mechanisms of conductivity were observed. Valence band transport dominated at higher temperatures, above 160 K, and activation energy of free-hole concentration was determined as about 0.20 eV. At lower temperatures hopping conductivity, clearly related to Mn defect band, was present. All these results were consistent with assumption of creation of Mn-related defect-band at 0.2 eV above InP valence band. It was found that Mn centers responsible for this band were in configurations of either d$\text{}^{5}$ or d$\text{}^{5}$ plus a hole localized about 7Å around corresponding Mn core.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 6; 637-642
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Localization Effects in GaN/AlGaN Quantum Well - Photoluminescence Studies
    Autorzy:
    Chwalisz, B.
    Wysmołek, A.
    Bożek, R.
    Korona, K. P.
    Stępniewski, R.
    Knap, W.
    Pakuła, K.
    Baranowski, J. M.
    Grandjean, N.
    Massies, J.
    Prystawko, P.
    Grzegory, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/2036024.pdf
    Data publikacji:
    2003-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    73.20.-r
    73.21.-b
    74.40.+k
    Opis:
    Exciton localization in GaN/AlGaN quantum well structures is studied by photoluminescence. An anomalous temperature behavior of the photoluminescence from the quantum well is observed. With increasing temperature the energy position of the excitonic emission line first decreases up to 20 K, then increases, reaching a maximum around 90 K, and then decreases again in the higher temperature range. The observed behavior is discussed in terms of localization at the interface potential fluctuations. It is argued that the temperature activated migration and subsequent release of the excitons from traps that occurs between 20 K and 90 K are responsible for the observed S-like shape of the energy dependence. The obtained results allow a direct characterization of the energy fluctuations present in GaN/AlGaN quantum wells grown by different techniques.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 6; 573-578
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Control of Photon Polarization in GaAs/AlAs Single Quantum Dot Emission
    Autorzy:
    Suffczyński, J.
    Trajnerowicz, A.
    Kazimierczuk, T.
    Piętka, B.
    Kowalik, K.
    Kossacki, P.
    Golnik, A.
    Nawrocki, M.
    Gaj, J. A.
    Wysmołek, A.
    Stępniewski, R.
    Potemski, M.
    Thierry-Mieg, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047725.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Cr
    78.66.Fd
    78.67.Hc
    78.47.+p
    Opis:
    We study polarization resolved correlation between photons emitted in cascaded biexciton-exciton recombination from a single quantum dot formed in type II GaAs/AlAs bilayer. Magnetic field induced transition from anisotropy controlled to the Zeeman controlled emission was demonstrated by a circular polarization correlation between the emitted photons. A simple model describing the effect allowed us to determine the anisotropic exchange splitting of the excitonic state. This method of the anisotropic exchange splitting determination can be useful in the case when other methods are not sensitive enough.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 461-466
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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