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    Tytuł:
    High Pressure Crystallization of III-V Nitrides
    Autorzy:
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1872352.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.10.-h
    Opis:
    Crystal growth from the solution under high N$\text{}_{2}$ pressure (HNP method) results in high quality mm size crystals of GaN in 5 to 24 hour process. The crystallization of AlN is less efficient due to relatively lower solubility of nitrogen in the liquid Al. Possibility of InN growth is strongly limited since this compound is unstable at T > 600°C even at 20 kbar. The growth of cm size high quality GaN crystals requires lower supersaturations and longer processes.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 295-302
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Electric Field on Recombination Dynamics of Quantum Confined Carriers
    Autorzy:
    Korona, K. P.
    Borysiuk, J.
    Skierbiszewski, C.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047384.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    72.20.Jv
    78.55.Cr
    Opis:
    We present time-resolved photoluminescence measurements of GaN/AlGaN low dimensional structures showing very characteristic changes of dynamics related to strong electric field. Strong piezoelectric and spontaneous polarizations built-in in nitride structures lead to the changes in spatial separation of carriers which leads to changes in recombination energies and radiative lifetimes of the carriers. The observed effect can be well described by a simple exponential relation. The observed dependence can be explained by an approximated model of quantum-confined Stark effect based on the Airy functions.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 243-247
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Application of High Pressure in Physics and Technology of III-V Nitrides
    Autorzy:
    Grzegory, I.
    Leszczyński, M.
    Krukowski, S.
    Perlin, P.
    Suski, T.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2030388.pdf
    Data publikacji:
    2001-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.10.-h
    78.66.Fd
    73.61.Ey
    82.60.Lf
    78.55.Cr
    Opis:
    Due to high bonding energy of N$\text{}_{2}$ molecule, the III-V semiconducting nitrides, especially GaN and InN require high N$\text{}_{2}$ pressure to be stable at high temperatures necessary for growth of high quality single crystals. Physical properties of GaN-Ga(l)-N$\text{}_{2}$ system are discussed in the paper. On the basis of the experimental equilibrium p-T-x data and the quantum-mechanical modeling of interaction of N$\text{}_{2}$ molecule with liquid Ga surface, the conditions for crystallization of GaN were established. The crystals obtained under high pressure are of the best structural quality, having dislocation density as low as 10-100 cm$\text{}^{-2}$ which is several orders of magnitude better than in any other crystals of GaN. The method allows to grow both n-type substrate crystals for optoelectronics and highly resistive crystals for electronic applications. The physical properties of the pressure grown GaN measured to characterize both point defects and extended defects in the crystal lattice are discussed in the paper. A special attention is paid to the application of high pressure to reveal the nature of the point defects in the crystals and electric fields in GaN-based quantum structures. Due to their very high structural quality, the pressure grown crystals are excellent substrates for epitaxial growth of quantum structures. It opens new possibilities for optoelectronic devices, especially short wavelength high power lasers and efficient UV light emitting diodes. This is due to the strong reduction in dislocation densities in relation to existing structures (10$\text{}^{6}$-10$\text{}^{8}$ cm$\text{}^{-2}$) which are grown on strongly mismatched sapphire and SiC substrates. The experimental results on the epitaxial growth and physical properties of GaN-based device structures supporting above conclusions are discussed in the paper. The current development of blue laser technology in High Pressure Research Center is shortly reviewed.
    Źródło:
    Acta Physica Polonica A; 2001, 100, Supplement; 57-109
    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:
    High Pressure Freeze-out of Electrons in Undoped GaN Crystal. Proof of Existence of Resonant Donor State (Nitrogen Vacancy)
    Autorzy:
    Perlin, P.
    Teisseyre, H.
    Suski, T.
    Leszczyński, M.
    Grzegory, I.
    Jun, J.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1931916.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.-i
    71.55.Eq
    Opis:
    We investigated free carriers related optical absorption in GaN in hydrostatic pressures up to 30 GPa. The disappearance of this absorption at pressures close to 18 GPa was explained by trapping electrons resulting from the shift of nitrogen vacancy related donor level into the GaN energy gap at high pressure. We estimated the energetic position of this level at atmospheric pressure to be about 0.8 eV above the conduction band minimum.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 141-143
    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:
    Crystallographic Properties of Bulk GaN Crystals Grown at High Pressure
    Autorzy:
    Leszczyński, M.
    Grzegory, I.
    Bockowski, M.
    Jun, J.
    Porowski, S.
    Jasiński, J.
    Baranowski, J. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933847.pdf
    Data publikacji:
    1995-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.72.Dd
    61.50.Cj
    Opis:
    Gallium nitride bulk crystals grown at about 15 kbar and 1500 K have been examined by using the high resolution X-ray diffractometry. An analysis of a set of the rocking curves of various Bragg reflections enabled us to estimate a dislocation density. For the crystals of dimensions lower than about 1 mm it is lower than 10$\text{}^{-5}$ cm$\text{}^{-2}$. For bigger samples the crystallographic quality worsens. With an application of the reciprocal lattice mapping we could distinguish between internal strains and mosaicity which are both present in these crystals The results for the bulk crystals are compared with those for epitaxial layers.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 4; 799-802
    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:
    Luminescence Dynamics of Exciton Replicas in Homoepitaxial GaN Layers
    Autorzy:
    Korona, K. P.
    Baranowski, J. M.
    Pakuła, K.
    Monemar, B.
    Bergman, J. P.
    Grzegory, I.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968240.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.-y
    78.47.+p
    78.55.Cr
    Opis:
    Photoluminescence of excitons and their phonon replicas in homoepitaxial MOCVD-grown gallium nitride (GaN) layers have been studied by picosecond (ps) time-resolved photoluminescence spectroscopy. The time-resolved photoluminescence spectroscopy has shown that the free excitons and their replicas have the fastest dynamics (decay time of about 100 ps). Then, the excitons-bound-to-donors emission rises (with the rise time similar to the free excitons decay time) and decays with t=300 ps. The excitons-bound-to-acceptors has the slowest decay (about 500 ps). It has been found that the ratio of excitons-bound-to-acceptors and excitons-bound-to-donors amplitudes and their decay times are different for 1-LO replicas and then for zero-phonon lines, whereas the ratio of amplitudes and the decay time of the 2-LO replicas are similar to the ones of the zero-phonon lines.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 841-844
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    III-V Semiconducting Nitrides Energy Gap under Pressure
    Autorzy:
    Perlin, P.
    Gorczyca, I.
    Teisseyre, H.
    Suski, T.
    Litwin-Staszewska, E.
    Porowski, S.
    Grzegory, I.
    Christensen, N. E.
    Powiązania:
    https://bibliotekanauki.pl/articles/1921585.pdf
    Data publikacji:
    1992-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.25.Tn
    Opis:
    In this paper we present overview of our recent experimental and theoretical results concerning electronic band structure of III-V nitrides under pressure. It is shown here that the pressure coefficients of the direct gap for studied nitrides are surprisingly small. To describe tendency in changes of the gap with pressure we use a simple empirical relation.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 4; 674-676
    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:
    Epitaxial Layers Versus Bulk Single Crystals of GaN. Temperature Studies of Lattice Parameters and Energy Gap
    Autorzy:
    Teisseyre, H.
    Perlin, P.
    Leszczyński, M.
    Suski, T.
    Dmowski, L.
    Grzegory, I.
    Porowski, S.
    Jun, J.
    Moustakas, T. D.
    Powiązania:
    https://bibliotekanauki.pl/articles/1873040.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    65.70.+y
    78.50.Ge
    78.66.Fd
    Opis:
    Gallium nitride epitaxial layer grown by molecular beam epitaxy and bulk crystal grown at high pressure were examined by using X-ray diffraction methods, and by optical absorption at a wide temperature range. The free electron concentration was 6 × 10$\text{}^{17}$ cm$\text{}^{-3}$ for the layer and about 5 × 10$\text{}^{19}$ cm$\text{}^{-3}$ for the bulk crystal. The experiments revealed a different position of the absorption edge and its temperature dependence for these two kinds of samples. The structural examinations proved a significantly higher crystallographic quality of the bulk sample. However, the lattice constants of the samples were nearly the same. This indicated that a rather different electron concentration was responsible for the different optical properties via Burstein-Moss effect.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 403-406
    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:
    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:
    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:
    Zastosowanie wysokiego cisnienia w atmosferze helu do obnizenia zanieczyszczenia mikrobiologicznego przypraw ziolowych
    High pressure processing of spices in atmosphere of helium for decrease of microbiological contamination
    Autorzy:
    Windyga, B
    Fonberg-Broczek, M.
    Sciezynska, H.
    Skapska, S.
    Gorecka, K.
    Grochowska, A.
    Morawski, A.
    Szczepek, J.
    Karlowski, K.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/877017.pdf
    Data publikacji:
    2008
    Wydawca:
    Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
    Tematy:
    przyprawy ziolowe
    zanieczyszczenia zywnosci
    zanieczyszczenia mikrobiologiczne
    dekontaminacja mikrobiologiczna
    wysokie cisnienia
    zastosowanie
    herbal spice
    food contaminant
    microbiological contaminant
    microbiological decontamination
    high pressure
    application
    Opis:
    Celem pracy było zbadanie możliwości zastosowania technologii wysokociśnieniowej (HPP) oraz podwyższonej temperatury w atmosferze gazu szlachetnego - helu - do redukcji zanieczyszczenia mikrobiologicznego w przyprawach ziołowych: owocach kolendry i nasionach kminku. Badane produkty poddawano działaniu ciśnienia 800 MPa i 1 000 MPa przez 30 minut w zakresie temperatur od 60 do 121°C. Stwierdzono redukcję mikroflory tlenowej o 2 cykle logarytmiczne, przy całkowitej inaktywacji bakterii z grupy coli oraz drożdży i pleśni. Zaobserwowano, że skuteczność procesu w atmosferze helu zależy od wilgotności środowiska i zabieg pozwala na redukcję zanieczyszczenia mikrobiologicznego przynajmniej przy 20% zawartości wody. Zastosowanie procesu HPP w atmosferze helu może być wykorzystanie do poprawy jakości mikrobiologicznej przypraw ziołowych.
    The aim of the study was to investigate the microbiological decontamination of coriander and caraway when HPP technology was applied in elevated temperature in helium atmosphere. The HPP and heat treatment was conducted for 30 minutes at 800 and 1 000 MPa and temperature range was 60 - 121°C. Contamination with aerobic mesophilic bacteria was decreased by about 2 logarithmic cycles. Total elimination of coliform and yeast and moulds was observed. The efficacy of HPP treatment under helium atmosphere depended on the content of the water in tested samples. It can be concluded that high pressure treatment under atmosphere of helium, combination of proper high pressure and time improved the microbiological quality of spices.
    Źródło:
    Roczniki Państwowego Zakładu Higieny; 2008, 59, 4; 437-443
    0035-7715
    Pojawia się w:
    Roczniki Państwowego Zakładu Higieny
    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:
    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:
    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:
    High Resistivity GaN Single Crystalline Substrates
    Autorzy:
    Porowski, S.
    Boćkowski, M.
    Łucznik, B.
    Grzegory, I.
    Wróblewski, M.
    Teisseyre, H.
    Leszczyński, M.
    Litwin-Staszewska, E.
    Suski, T.
    Trautman, P.
    Pakuła, K.
    Baranowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968415.pdf
    Data publikacji:
    1997-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    72.80.Ey
    Opis:
    High resistivity 10$\text{}^{4}$-10$\text{}^{6}$ Ω cm (300 K) GaN single crystals were obtained by solution growth under high N$\text{}_{2}$ pressure from melted Ga with 0.1-0.5at.% of Mg. Properties of these crystals are compared with properties of conductive crystals grown by a similar method from pure Ga melt. In particular, it is shown that Mg-doped GaN crystals have better structural quality in terms of FWHM of X-ray rocking curve and low angle boundaries. Temperature dependence of electrical resistivity suggests hopping mechanism of conductivity. It is also shown that strain free GaN homoepitaxial layers can be grown on the Mg-doped GaN substrates.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 5; 958-962
    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
    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:
    Cathodoluminescence Profiling of InGaN-Based Quantum Well Structures and Laser Diodes - In-Plane Instabilities of Light Emission
    Autorzy:
    Godlewski, M.
    Ivanov, V. Yu.
    Goldys, E. M.
    Phillips, M.
    Böttcher, T.
    Figge, S.
    Hommel, D.
    Czernecki, R.
    Prystawko, P.
    Leszczynski, M.
    Perlin, P.
    Grzegory, I.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2036870.pdf
    Data publikacji:
    2003-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.72.Ff
    61.72.Mm
    68.37.Hk
    78.60.Hk
    Opis:
    Instabilities of light emission and also of stimulated emission in series of GaN epilayers and InGaN quantum well structures, including laser diode structures, are studied. A stimulated emission is observed under electron beam pumping. This enabled us to study light emission properties from laser structures and their relation to microstructure details. We demonstrate large in-plane fluctuations of light emission and that these fluctuations are also present for excitation densities larger than the threshold densities for the stimulated emission.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 6; 689-694
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    High temperature stability of electrical and optical properties of bulk GaN:Mg grown by HNPS method in different crystallographic directions
    Autorzy:
    Sadovyi, B.
    Amilusik, M.
    Staszczak, G.
    Bockowski, M.
    Grzegory, I.
    Porowski, S.
    Konczewicz, L.
    Tsybulskyi, V.
    Panasyuk, M.
    Rudyk, V.
    Karbovnyk, I.
    Kapustianyk, V.
    Litwin-Staszewska, E.
    Piotrzkowski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1159722.pdf
    Data publikacji:
    2016-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    72.80.Ey
    Opis:
    Single crystals of Mg-doped GaN grown by high nitrogen pressure solution method in different crystallographic directions ([0001], [101̅1], and [101̅1̅]) were investigated in order to determine thermal stability of their electrical and optical properties. Obtained dependences of resistivity, the Hall coefficient and energy shift of Mg-related photoluminescence peak on annealing temperature allow to suggest that incorporation of Mg in GaN is significantly influenced by the direction of the crystallization front.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 1a; A-126-A-128
    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:
    Relationship between Sample Morphology and Carrier Diffusion Length in GaN Thin Films
    Autorzy:
    Godlewski, M.
    Goldys, E. M.
    Phillips, M.
    Böttcher, T.
    Figge, S.
    Hommel, D.
    Czernecki, R.
    Prystawko, P.
    Leszczynski, M.
    Perlin, P.
    Wisniewski, P.
    Suski, T.
    Bockowski, M.
    Grzegory, I.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035593.pdf
    Data publikacji:
    2002
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.72.Ff
    61.72.Mm
    68.37.Hk
    78.60.Hk
    Opis:
    Scanning and spot-mode cathodoluminescence investigations of homo- and hetero-epitaxial GaN films indicate a surprisingly small influence of their microstructure on overall intensity of a light emission. This we explain by a correlation between structural quality of these films and diffusion length of free carriers and excitons. Diffusion length increases with improving structural quality of the samples, which, in turn, enhances the rate of nonradiative recombination on structural defects, such as dislocations.
    Źródło:
    Acta Physica Polonica A; 2002, 102, 4-5; 627-632
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Blue Laser on High N$\text{}_{2}$ Pressure-Grown Bulk GaN
    Autorzy:
    Grzegory, I.
    Boćkowski, M.
    Krukowski, S.
    Łucznik, B.
    Wróblewski, M.
    Weyher, J.
    Leszczyński, M.
    Prystawko, P.
    Czernecki, R.
    Lehnert, J.
    Nowak, G.
    Perlin, P.
    Teisseyre, H.
    Purgał, W.
    Krupczyński, W.
    Suski, T.
    Dmowski, L.
    Litwin-Staszewska, E.
    Skierbiszewski, C.
    Łepkowski, S.
    Porowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2030423.pdf
    Data publikacji:
    2001-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Opis:
    In this note we report briefly on the details of pulsed-current operated "blue" laser diode, constructed in our laboratories, which utilizes bulk GaN substrate. As described in Ref. [1] the substrate GaN crystal was grown by HNPSG method, and the laser structure was deposited on the conducting substrate by MOCVD techniques (for the details see Sec. 2 and Sec. 4 of Ref.~[1], respectively).
    Źródło:
    Acta Physica Polonica A; 2001, 100, Supplement; 229-232
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Propozycje poprawy zarządzania bezpieczeństwem w cyklu transportowym przewozów drogowych towarów niebezpiecznych
    Proposals for improvement of safety management in the cycle of road transport of dangerous goods
    Autorzy:
    Michalik, J. S.
    Gajek, A.
    Janik, P.
    Zając, S.
    Koniuch, A.
    Obolewicz, A.
    Porowski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/180892.pdf
    Data publikacji:
    2011
    Wydawca:
    Centralny Instytut Ochrony Pracy
    Tematy:
    transport drogowy
    transport chemikaliów
    transport towarów niebezpiecznych
    road transport
    liquid fuels
    dangerous goods transport
    Opis:
    Uwzględniając główną przyczynę zdarzeń awaryjnych w przewozie drogowym towarów niebezpiecznych - niezachowanie zasad bezpieczeństwa ruchu - określono rodzaje środków i działań umożliwiających poprawę bezpieczeństwa ich transportu. Wykonane analizy wykazały, że system szkolenia osób związanych z przewozem towarów niebezpiecznych, system organizacyjny jednostek ratownictwa PSP oraz procedury reagowania i zwalczania skutków awarii transportowych są zorganizowane w Polsce na wysokim poziomie i funkcjonują prawidłowo. W tej sytuacji zmniejszenie ryzyka wypadku drogowego o cechach poważnej awarii można osiągnąć w wyniku wyboru najbardziej właściwej trasy przewozowej. Została zaproponowana metoda wyboru najkorzystniejszej z punktu widzenia poziomu ryzyka przebiegu trasy przewozu towarów niebezpiecznych, oparta na ocenie pasa terenu 1,5 km od osi drogi pod względem demograficznym oraz występowania obiektów użyteczności publicznej i elementów środowiska o szczególnej wrażliwości, a także na ocenie szeregu parametrów techniczno-konstrukcyjnych trasy, dotyczących podstawowych cech ruchu drogowego.
    This article defines the types of measures and actions for improving safety of road transport of dangerous goods taking into account the main cause of accidents with the attributes of major accidents in road transport of dangerous goods, i. e., disregard for traffic rules. Analyses showed that the system of training persons involved in transport of dangerous goods, the organizational system of the State Fire Service rescue units, and the procedures for responding and mitigating the effects of transport accidents in Poland are good and that they function properly. In this situation, selecting the most appropriate transport routes can reduce the risk of an accident with the attributes of a major accident. This article proposes a method of selecting the least risky transport route for dangerous goods by evaluating a strip of land 15 km from the axis of the road in terms of demographics, public Utilities, particularly sensitive environment as well as by evaluating a number of technical and construction parameters of routes related to the basie features of road traffic.
    Źródło:
    Bezpieczeństwo Pracy : nauka i praktyka; 2011, 5; 24-27
    0137-7043
    Pojawia się w:
    Bezpieczeństwo Pracy : nauka i praktyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-28 z 28

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