Search results

1

Oxygen Precipitation in Si:O Annealed under High Hydrostatic Pressure

100%

Misiuk A., Bąk-Misiuk J., Bryja L., Kątcki J., Ratajczak J., Jun J., Surma B.

Acta Physica Polonica A

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2002

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vol. 101

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issue 5

719-727

EN

Effect of hydrostatic pressure up to 1.2 GPa on oxygen-implanted silicon, Si:O (O^+ dose, D, within the 6×10^{17}-2×10^{18} cm^{-2} range), treated at 1230-1570 K, was investigated by X-ray, transmission electron microscopy and photoluminescence methods. The pressure treatment affects oxygen precipitation and defect creation, especially in low oxygen dose implanted Si:O (D=6×10^{17} cm^{-2}). Such investigation helps in understanding the stress related phenomena in Si wafers with buried insulating layer.

2

High Pressure Freeze-out of Electrons in Undoped GaN Crystal. Proof of Existence of Resonant Donor State (Nitrogen Vacancy)

100%

Perlin P., Teisseyre H., Suski T., Leszczyński M., Grzegory I., Jun J., Porowski S.

Acta Physica Polonica A

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1995

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vol. 87

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issue 1

141-143

EN

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.

3

Optical and Electrical Properties of High Temperature Annealed Heteroepitaxial GaN:Mg Layers

100%

Wojdak M., Baranowski J. M., Suchanek B., Pakuła K., Jun J., Suski T.

Acta Physica Polonica A

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1997

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vol. 92

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issue 5

1059-1062

EN

In this paper we present for the first time luminescence and electrical measurements of GaN:Mg heteroepitaxial layers annealed at very high temperatures up to 1500°C and at high pressures of nitrogen up to 16 kbar. The presence of high nitrogen pressure prevents GaN from thermal decomposition. It was found that annealing in the presence of additional Mg atmosphere leads to a high quality p-type epitaxial layer of the hole concentration equal to 2×10^{17} cm^{-3} and mobility 16 cm^{2}/(V s). However, annealing at high temperatures without additional magnesium causes conversion to n-type. It is also shown that in the high temperature annealed GaN:Mg epilayers the donor-acceptor luminescence is the dominant recombination channel.

4

Crystallographic Properties of Bulk GaN Crystals Grown at High Pressure

100%

Leszczyński M., Grzegory I., Bockowski M., Jun J., Porowski S., Jasiński J., Baranowski J. M.

Acta Physica Polonica A

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1995

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vol. 88

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issue 4

799-802

EN

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^{-5} cm^{-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.

5

Growth of GaN Metalorganic Chemical Vapour Deposition Layers on GaN Single Crystals

84%

Pakula K., Baranowski J. M., Stępniewski R., Wysmołek A., Grzegory I., Jun J., Porowski S., Sawicki M., Starowieyski K.

Acta Physica Polonica A

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1995

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vol. 88

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issue 5

861-864

EN

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.

6

Epitaxial Layers Versus Bulk Single Crystals of GaN. Temperature Studies of Lattice Parameters and Energy Gap

84%

Teisseyre H., Perlin P., Leszczyński M., Suski T., Dmowski L., Grzegory I., Porowski S., Jun J., Moustakas T.

Acta Physica Polonica A

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1995

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vol. 87

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issue 2

403-406

EN

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^{17} cm^{-3} for the layer and about 5 × 10^{19} cm^{-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.

7

Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers

68%

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

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1996

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vol. 90

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issue 5

887-890

EN

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.

Refine search results

Oxygen Precipitation in Si:O Annealed under High Hydrostatic Pressure

High Pressure Freeze-out of Electrons in Undoped GaN Crystal. Proof of Existence of Resonant Donor State (Nitrogen Vacancy)

Optical and Electrical Properties of High Temperature Annealed Heteroepitaxial GaN:Mg Layers

Crystallographic Properties of Bulk GaN Crystals Grown at High Pressure

Growth of GaN Metalorganic Chemical Vapour Deposition Layers on GaN Single Crystals

Epitaxial Layers Versus Bulk Single Crystals of GaN. Temperature Studies of Lattice Parameters and Energy Gap

Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers