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Wyszukujesz frazę "Porowski, A." wg kryterium: Autor


Wyświetlanie 1-13 z 13
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:
Measurement of Very Small Zeeman Splittings in GaN:Mn,Mg by Faraday Rotation
Autorzy:
Wołoś, A.
Kossacki, P.
Golnik, A.
Kamińska, M.
Gaj, J. A.
Twardowski, A.
Grzegory, I.
Boćkowski, M.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035615.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
71.70.Ej
71.55.Eq
71.20.Nr
Opis:
In this work we demonstrate an application of Faraday rotation for measuring an extremely small Zeeman splitting of an Mn related absorption line placed at 1.417 eV in optical absorption spectrum of Mn and Mg doped gallium nitride. Analysis of the collected spectra allowed us to determine the value of the splitting as equal to 0.12±0.01 meV at 6 T. This data should help in establishing the nature of the observed absorption band.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 695-699
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mn Impurity in GaN Studied by Electron Paramagnetic Resonance
Autorzy:
Wołoś, A.
Palczewska, M.
Wilamowski, Z.
Kamińska, M.
Twardowski, A.
Boćkowski, M.
Grzegory, I.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2036027.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
71.55.Eq
71.70.Gm
Opis:
We present the results of electron paramagnetic resonance investigations of GaN bulk crystals doped with Mn. The EPR experiment shows the Mn$\text{}^{2+}$ resonance in all the investigated n-type crystals, while in highly resistive samples extra doped with Mg acceptor the Mn$\text{}^{2+}$ resonance decreases. This is a consequence of the location of Mn acceptor level in GaN band gap. The analysis of the spin relaxation times reveals the Korringa scattering as the dominating spin relaxation mechanism in n-type GaN:Mn crystals. The effective exchange constant determined from spin relaxation rate temperature dependence is of the order of 14 meV.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 595-600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation of Magnetic Anisotropy in Bulk GaMnN:Mg Crystals
Autorzy:
Gosk, J.
Zając, M.
Kamińska, M.
Twardowski, A.
Grzegory, I.
Boćkowski, M.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2036861.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
75.30.Gw
75.50.Pp
Opis:
Magnetic properties of bulk wurtzite n-type GaMnN and highly resistive GaMnN:Mg monocrystals were studied for the magnetic field applied parallel and perpendicular to the crystal hexagonal c-axis. Magnetization of both types of samples reveals paramagnetic behavior. However, for n-type GaMnN isotropic magnetization was observed which is in agreement with Mn d$\text{}^{5}$ configuration. On the other hand, GaMnN co-doped with Mg shows large magnetic anisotropy which suggests Mn to be in nonspherical d$\text{}^{4}$ or d$\text{}^{3}$ configuration.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 665-669
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MnAs Overlayer on GaN(000$\text{}_{1}$)-(1 x 1) - Its Growth, Morphology and Electronic Structure
Autorzy:
Kowalski, B. J.
Kowalik, I. A.
Iwanowski, R. J.
Łusakowska, E.
Sawicki, M.
Sadowski, J.
Grzegory, I.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2038151.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.-a
73.20.At
Opis:
MnAs layer has been grown by means of MBE on the GaN(000$\text{}_{1}$)-(1 x 1) surface. Spontaneous formation of MnAs grains with a diameter of 30-60 nm (as observed by atomic force microscopy) occurred for the layer thickness bigger than 7 ML. Ferromagnetic properties of the layer with Curie temperature higher than 330 K were detected by SQUID measurements. Electronic structure of the system was investigated in situ by resonant photoemission spectroscopy for MnAs layer thickness of 1, 2, and 8 ML. Density of the valence band states of MnAs and its changes due to the increase in the layer thickness were revealed.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 645-650
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:
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:
Optically Pumped Laser Action on Nitride Based Separate Confinement Heterostructures Grown along the (11¯20) Crystallographic Direction
Autorzy:
Teisseyre, H.
Szymański, M.
Khachapuridze, A.
Skierbiszewski, C.
Feduniewicz-Żmuda, A.
Siekacz, M.
Łucznik, B.
Kamler, G.
Kryśko, M.
Suski, T.
Perlin, P.
Grzegory, I.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047728.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Px
78.45.+h
78.66.Fd
Opis:
The intention of this work is to discuss and report on our research on nonpolar laser structures grown on bulk GaN crystal substrates along the (11¯20) nonpolar direction. The main advantages of such nonpolar structures are related to the elimination of the built-in electric fields present in commonly used systems grown along the polar (0001) axis of nitride crystals. We demonstrated the optically pumped laser action on separate confinement heterostructures. Laser action is clearly shown by spontaneous emission saturation, abrupt line narrowing, and strong transversal electric polarization of output light. The lasing threshold was reached at an excitation power density of 260 kW/cm$\text{}^{2}$ for a 700μm long cavity (at room temperature).
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 467-472
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanisms of Yellow and Red Photoluminescence in Wurtzite and Cubic GaNDOI
Autorzy:
Godlewski, M.
Suski, T.
Grzegory, I.
Porowski, S.
Langer, R.
Barski, A.
Bergman, J. P.
Monemar, B.
Goldys, E. M.
Phillips, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/1969079.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.Ch
61.72.Ff
71.55.Eq
Opis:
The origin of two "deep" photoluminescence (PL) emissions observed in wurtzite (yellow PL) and cubic (red PL) GaN is discussed. PL and time-resolved PL studies confirm donor-acceptor pair character of the yellow band in wurtzite GaN and point to participation of shallow donors in this emission. A similar PL mechanism is proposed for the red emission of cubic GaN. We further show a puzzling property of both yellow and red PLs. Both yellow and red emissions show spatial homogeneity and are only weakly dependent on surface morphology.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 326-330
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers
Autorzy:
Leszczyński, M.
Teisseyre, H.
Suski, T.
Grzegory, I.
Boćkowski, M.
Jun, J.
Pałosz, B.
Porowski, S.
Pakuła, K.
Baranowski, J. M.
Barski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1952040.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
61.72.Vv
Opis:
Thermal expansion of gallium nitride was measured using high resolution X-ray diffraction. The following samples were examined: (i) single monocrystals grown at pressure of about 15 kbar, (ii) homoepitaxial layers. The main factor influencing both, the lattice parameters and the thermal expansion coefficient, are free electrons related to the nitrogen vacancies. The origin of an increase in the lattice constants by free electrons is discussed in terms of the deformation potential of the conduction-band minimum. An increase of the thermal expansion by free electrons is explained by a decrease of elastic constants.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 887-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Power Continuous Wave Blue InAlGaN Laser Diodes Made by Plasma Assisted MBE
Autorzy:
Skierbiszewski, C.
Siekacz, M.
Wiśniewski, P.
Perlin, P.
Feduniewicz-Żmuda, A.
Cywiński, G.
Smalc, J.
Grzanka, S.
Grzegory, I.
Leszczyński, M.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047002.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Px
85.35.Be
42.60.By
73.21.Cd
Opis:
Room temperature, continuous wave operation of InGaN multi-quantum wells laser diodes made by rf plasma assisted molecular beam epitaxy at 411 nm wavelength is demonstrated. The threshold current density and voltage were 4.2 kA/cm$\text{}^{2}$ and 5.3 V, respectively. High optical power output of 60 mW was achieved. The lifetime of these laser diodes exceeds 5 h with 2 mW of optical output power. The laser diodes are fabricated on low dislocation density bulk GaN substrates, at growth conditions which resembles liquid phase epitaxy. We demonstrate that relatively low growth temperatures (600-700°C) pose no intrinsic limitations for fabrication of nitride optoelectronic components by plasma assisted molecular beam epitaxy.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 345-351
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarity Related Problems in Growth of GaN Homoepitaxial Layers
Autorzy:
Leszczyński, M.
Prystawko, P.
Śliwinski, A.
Suski, T.
Litwin-Staszewska, E.
Porowski, S.
Paszkiewicz, R.
Tłaczała, M.
Beaumont, B.
Gibart, P.
Barski, A.
Langer, R.
Knap, W.
Frayssinet, E.
Powiązania:
https://bibliotekanauki.pl/articles/1991873.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Vv
65.70.+y
Opis:
Homoepitaxial layers of GaN were grown by metalorganic chemical vapour deposition on single crystals obtained by high-pressure, high-temperature technology. For each metalorganic chemical vapour deposition run, four samples were placed, (00.1) and (00.1̲) faces of the Mg-doped insulating and undoped highly-conductive substrates. The layers were examined using X-ray diffraction, photoluminescence and far-infrared reflectivity. It was found that the (00.1̲) easier incorporates donors resulting in higher free-electron concentrations in the layers grown on these sides of the crystals, both, undoped and Mg-doped.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 427-430
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crack Free GaInN/AlInN Multiple Quantum Wells Grown on GaN with Strong Intersubband Absorption at 1.55μm
Autorzy:
Cywiński, G.
Skierbiszewski, C.
Feduniewicz-Żmuda, A.
Siekacz, M.
Nevou, L.
Doyennette, L.
Julien, F. H.
Prystawko, P.
Kryśko, M.
Grzanka, S.
Grzegory, I.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2046911.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.65.Fg
78.66.-w
78.67.De
78.40.Fy
81.15.Hi
Opis:
Crack free GaInN/AlInN multiple quantum wells were grown by rf plasma-assisted molecular beam epitaxy on (0001) GaN/sapphire substrates. The strain-engineering concept was applied to eliminate cracking effect for growth of intersubband structures on GaN. Indium contained ternary compounds of barrier and well layers are contrary strained to the substrate material. A series of crack free GaInN/AlInN intersubband structures on (0001) GaN was fabricated and investigated. The assumed composition and layered structure were confirmed by room temperature photoluminescence and X-ray diffraction measurements. The intersubband measurements were done in multipass waveguide geometry by applying direct intersubband absorption and photoinduced intersubband absorption measurements. The optimized structure design contains forty periods of Si-doped GaInN/AlInN quantum wells and exhibits strong intersubband absorption.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 175-181
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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