Search results

1

Light Induced Recovery of EL2 Defect from the Metastable Configuration

100%

Teisseyre H., Kuszko W.

Acta Physica Polonica A

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1991

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vol. 79

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issue 2-3

267-270

EN

The measurements: of changes in a magnitude of ΕL2 characteristic infrared absorption were used to investigate a phenomenon of light induced recovery of the defect from its metastable state in semi-insulating (SI) and n-type GaAs. At a temperature of 12K illumination with photons of energy 1.45 eV caused partial recovery for both SI and n-type samples. For n-type samples partial recovery occurred also after irradiation with photons of energy lower than 0.73 eV.

2

Effect of the Built-In Strain on the In-Plane Optical Anisotropy of m-Plane GaN/AlGaN Quantum Wells

81%

Łepkowski S., Bardyszewski W., Teisseyre H.

Acta Physica Polonica A

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2011

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vol. 120

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issue 5

897-898

EN

We study theoretically the influence of the anisotropic biaxial strain originating from the lattice mismatch between the m-plane GaN/AlGaN quantum wells structure and the substrate on the optical anisotropy of such systems. It is demonstrated that the oscillator strengths for optical transitions with polarization of light parallel and perpendicular to the crystal axis c strongly depend on strain to such an extent that, by increasing the concentration of Al in the substrate from x = 0 to x = 0.5 one can change the polarization of the emitted light with respect to the c-axis by 90 degrees.

3

Pressure Dependence of Exciton Binding Energy in GaN/Al_{x}Ga_{1 - x}N Quantum Wells

81%

Bardyszewski W., Łepkowski S., Teisseyre H.

Acta Physica Polonica A

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2011

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vol. 119

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issue 5

663-665

EN

We present a theoretical study of excitons in GaN/Al_{x}Ga_{1 - x}N wurtzite (0001) quantum wells subjected to hydrostatic pressure. Our results show that the combined effect of pressure induced changes in band structure and piezoelectric field leads to reduction of the exciton binding energy. This subtle effect is described quite accurately by our multiband model of excitons in quantum wells.

4

Band Structure and Refractive Index of Gallium Nitride Under Pressure

62%

Perlin P., Gorczyca I., Suski T., Teisseyre H., Grzegory I., Christensen N.

Acta Physica Polonica A

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1991

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vol. 80

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issue 3

421-424

EN

The effect of hydrostatic pressure on direct gap and refractive index of GaN is investigated up to 5.5 GPa. Band structure of GaN is calculated by Linear Muffin-Tin Orbitals (LMTO) method for different values of pressure. Resulting pressure coefficient of the main gap and of the refractive index are in a good agreement with the experimental ones.

5

The Role of Internal Electric Fields in III-N Quantum Structure

62%

Perlin P., Łepkowski S., Teisseyre H., Suski T., Grandjean N., Massies J.

Acta Physica Polonica A

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2001

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vol. 100

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issue 2

261-270

EN

Binary nitrides: of wurtzite GaN, AlN, InN, and their solid solutions represent a family of semiconductors of crucial importance for modern optoelectronics. Strained quantum wells, like GaN/AlGaN and specially InGaN/GaN, form active layers of the light emitters working in green-UV part of the spectrum. The operation of these devices strongly depends on the emission spectra of considered quantum structures which are greatly influenced by the presence of built-in electric fields. The electric field acting via quantum confined Stark effect in the mentioned structures changes the energies and intensity of the emitted light. The effect can lead to the spectral shift of a photo- and electroluminescence by many hundreds of meV. In this review we will briefly cover the influence of internal electric fields on both optical and electrical properties of nitride based heterostructures and quantum wells. We would like to draw reader's attention to the usefulness of high-pressure investigation in the study of electric fields in nitrides and to show how the interpretation of these experiments influences the way we calculate the electric fields in the quantum structures.

6

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

62%

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

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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.

7

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

52%

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.

8

III-V Semiconducting Nitrides Energy Gap under Pressure

52%

Perlin P., Gorczyca I., Teisseyre H., Suski T., Litwin-Staszewska E., Porowski S., Grzegory I., Christensen N.

Acta Physica Polonica A

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1992

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vol. 82

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issue 4

674-676

EN

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.

9

Optically Pumped Laser Action on Nitride Based Separate Confinement Heterostructures Grown along the (11¯20) Crystallographic Direction

42%

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.

Acta Physica Polonica A

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2007

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vol. 112

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issue 2

467-472

EN

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^2 for a 700μm long cavity (at room temperature).

10

High Resistivity GaN Single Crystalline Substrates

42%

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.

Acta Physica Polonica A

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1997

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vol. 92

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issue 5

958-962

EN

High resistivity 10^{4}-10^{6} Ω cm (300 K) GaN single crystals were obtained by solution growth under high N_{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.

11

Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers

42%

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.

12

Blue Laser on High N_2 Pressure-Grown Bulk GaN

33%

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.

Acta Physica Polonica A

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2001

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vol. 100

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issue Supplement

229-232

EN

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).

Refine search results

Light Induced Recovery of EL2 Defect from the Metastable Configuration

Effect of the Built-In Strain on the In-Plane Optical Anisotropy of m-Plane GaN/AlGaN Quantum Wells

Pressure Dependence of Exciton Binding Energy in GaN/Al_{x}Ga_{1 - x}N Quantum Wells

Band Structure and Refractive Index of Gallium Nitride Under Pressure

The Role of Internal Electric Fields in III-N Quantum Structure

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

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

III-V Semiconducting Nitrides Energy Gap under Pressure

Optically Pumped Laser Action on Nitride Based Separate Confinement Heterostructures Grown along the (11¯20) Crystallographic Direction

High Resistivity GaN Single Crystalline Substrates

Thermal Expansion of GaN Bulk Crystals and Homoepitaxial Layers

Blue Laser on High N_2 Pressure-Grown Bulk GaN