Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

5 Acta Physica Polonica A

Znaleziono wyników: 5

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Optical Properties of GaN Epilayers grown by Gas Source Molecular Beam Epitaxy on AlN Buffer Layer on (111) Si

100%

Godlewski M. , Bergman J. , Monemar B. , Rossner U. , Barski A.

Acta Physica Polonica A

1996

tom 90

nr 4

789-792

Optical properties of GaN/AlN/Si (111) epilayers grown by MBE are studied. The observed decay transients of excitonic emissions and their temperature dependence is explained by an efficient transfer link between bound and free excitons.

Photoluminescence Studies of Cubic Phase GaN Grown by Molecular Beam Epitaxy on (001) Silicon Covered with Sic Layer

86%

Godlewski M. , Ivanov V. , Bergman J. , Monemar B. , Barski A. , Langer R.

Acta Physica Polonica A

1997

tom 92

nr 4

777-780

In this work we evaluate optical properties of cubic phase GaN epilayers grown on top of (001) silicon substrate prepared by a new process. Prior to the growth Si substrate was annealed at 1300-1400°C in propane. The so-prepared substrate is covered with a thin (≈ 4 nm) SiC wafer, which allowed a successful growth of good morphological quality cubic phase GaN epilayers. The present results confirm recent suggestion on smaller ionization energies of acceptors in cubic phase GaN epilayers.

Mechanisms of Yellow and Red Photoluminescence in Wurtzite and Cubic GaN

72%

Godlewski M. , Suski T. , Grzegory I. , Porowski S. , Langer R. , Barski A. , Bergman J. , Monemar B. , Goldys E. , Phillips M.

Acta Physica Polonica A

1998

tom 94

nr 2

326-330

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.

Polarity Related Problems in Growth of GaN Homoepitaxial Layers

58%

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.

Acta Physica Polonica A

1998

tom 94

nr 3

427-430

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.

Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers

58%

Leszczyński M. , Teisseyre H. , Suski T. , Grzegory I. , Boćkowski M. , Jun J. , Pałosz B. , Porowski S. , Pakuła K. , Baranowski J. , Barski A.

Acta Physica Polonica A

1996

tom 90

nr 5

887-890

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.