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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:
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:
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:
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:
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:
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:
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 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:
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:
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:
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:
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:
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:
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
Wyświetlanie 1-15 z 28

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