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1

Grey Solitons in Saturable Media with Nonlinear Dispersion and Self-Frequency Shift

100%

Jasiński J.

Acta Physica Polonica A

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2003

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vol. 103

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issue 2-3

149-160

EN

In the paper a special form of the generalized nonlinear Schrödinger equation in saturable medium with nonlinear dispersion and the self-frequency shift terms is considered. The solutions describing both the intensity and phase profiles of grey solitons propagating in this medium are obtained. Four cases of medium with or without saturation and with or without higher order terms are considered. For a square-two-level model of saturation analytical explicit solutions are derived. The relations between the medium and propagation parameters of solitons are discussed.

2

Bright and Dark Solitons in Generalized Kerr-Like Media

100%

Jasiński J.

Acta Physica Polonica A

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2001

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vol. 99

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issue 1

77-86

EN

In the paper the propagation of short pulses in nonlinear Kerr-like medium is considered. Pulses are described by the nonlinear Schrödinger equation in which the generalization of nonlinear dispersion term and the self-frequency shift are taken into account. The solution of the equation in the form of quadrature is derived. Both the phase and profile of the pulse intensity are obtained. The cases of propagating bright and dark solitons in saturable Kerr-like medium are analyzed. Two models of saturation are considered. The explicit analytical expressions describing the Kerr limit are reported. The relations between the medium and propagation parameters are thoroughly discussed.

3

Recrystallization of Amorphous Layer in Ion Implanted GaAs - Transmission Electron Microscopy Studies

64%

Jasiński J., Liliental-Weber Z.

Acta Physica Polonica A

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1996

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vol. 90

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issue 4

825-828

EN

2 MeV arsenic or gallium ions were used to produce nonstoichiometric buried amorphous layers in gallium arsenide. The mechanism of thermally induced regrowth of these layers was investigated using transmission electron microscopy. Low-temperature annealing resulted in nucleation of high densities of stacking faults. This was associated with the local nonstoichiometry of the amorphous layers. After annealing at high temperatures, in arsenic as well as in gallium implanted samples, two layers of voids, formed in result of vacancies clustering, were found in areas adjacent to the initial location of the amorphous-crystalline interfaces. A qualitative model of the formation of such layers was proposed.

4

Antisites Defects in GaP

51%

Jasiński J., Kamińska M., Palczewska M., Jurkiewicz-Wagner P.

Acta Physica Polonica A

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1993

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vol. 84

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issue 3

579-582

EN

ESR, optical, and transport measurements were done on neutron-irradiated GaP crystals subjected to thermal annealing. The behavior of two dominant paramagnetic defects: phosphorus antisite PP4 and WA1 [1] was followed. ESR signal similar to WA1 was earlier attributed to the defect related with gallium antisite [2]. Our thermal annealing experiments supported such attribution. Apart from that, the obtained results indicated that two dominant absorption bands in neutron-irradiated GaP with maxima at 0.79 and 1.13 eV [1] were not connected with PP_{4} or WA1 defects. However, one of these paramagnetic defects (or two of them) were responsible for hopping transport in n-irradiated GaP crystals.

5

Investigation of Quantum Dot Structures Grown by MOCVD in InAs/GaAs System

51%

Jasiński J., Bożek R., Stępniewski R., Kozubowski J.

Acta Physica Polonica A

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1998

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vol. 94

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issue 3

369-373

EN

Layers of InAs quantum dots grown on [100] GaAs substrates were characterised by photoluminescence and investigated by transmission electron microscopy. Two types of InAs islands were observed in these layers. The islands of the first type had mainly a form of big, elongated pyramids. Most of them were found to be dislocated. On the other hand, the islands of the second type were real self-assembled, coherent quantum dots giving rise to a characteristic photoluminescence band.

6

Photo-ESR and Absorption Studies of Antisite Defects in GaP

51%

Palczewska M., Jasiński J., Kamińska M.

Acta Physica Polonica A

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1995

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vol. 87

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issue 2

461-464

EN

Photo-ESR and optical absorption measurements were done on annealed neutron irradiated GaP crystals. The position of paramagnetic gallium anti-site level in GaP energy gap has been determined. Additionally, the position of paramagnetic phosphorus antisite level, earlier determined in the paper of Kruger and Alexander, has been confirmed. Moreover, unusual in ESR experiments temperature dependence of phosphorus antisite amplitude in neutron irradiated GaP crystals has been explained.

7

Crystallographic Properties of Bulk GaN Crystals Grown at High Pressure

39%

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.

8

Defects Studies in As Grown and Neutron Irradiatcd Phosphorus Rich GaP

39%

Jasiński J., Palczewska M., Korona K., Kamińska M., Bourret E., Elliot G.

Acta Physica Polonica A

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1992

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vol. 82

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issue 5

829-832

EN

Semi-insulating, p- and n-type liquid encapsulated Czochralski grown phosphorus rich GaP crystals before and alter neutron irradiation were studied. EPR measurements proved that the phosphorus antisite defect P_{Ga} introduced by neutron irradiation was exactly the same as in as grown materials, i.e. surrounded by four substitutional phosphorus atoms. In neutron irradiated crystals EPR showed also a signal, similar to the one found in plastically deformed GaAs and GaP. The concentrations of P_{Ga} and of the other defect were estimated to be of the same order of magnitude. Two absorption bands at 0.81 and 1.12 eV were found for irradiated materials. The temperature dependence of resistivity indicated hopping as the mechanism of conduction in samples irradiated with doses higher than 4 × 10^{16} cm^{-2}.

9

Interfacial Microstructure of Ni/Si-Based Ohmic Contacts To GaN

33%

Kamińska E., Piotrowska A., Jasiński J., Kozubowski J., Barcz A., Gołaszewska K., Bremser M., Davis R.

Acta Physica Polonica A

|

1998

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vol. 94

|

issue 3

383-386

EN

The microstructure of Ni/Si-based contacts to GaN has been studied using transmission electron microscopy methods. The transition from non-ohmic to ohmic behavior appears to correlate with the initial limited reaction of GaN with Ni and further Si-Ni reaction-driven decomposition of the interfacial GaN-Ni phase.

10

Ultrafast Carrier Trapping and High Resistivity of MeV Energy Ion Implanted GaAs

33%

Korona K., Jasiński J., Kurpiewski A., Kamińska M., Jagadish C., Tan H., Krotkus A., Marcinkevicius S.

Acta Physica Polonica A

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1996

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vol. 90

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issue 4

851-854

EN

Semi-insulating GaAs wafers were implanted with MeV As, Ga, O or Si ions at doses ranging from 1×10^{14} to 5×10^{16} cm^{-2}. Their structural properties were studied by electron microscopy and the Rutherford backscattering-channeling. Time resolved photoluminescence, electrical conductivity and the Hall effect were used to determine carrier lifetime and electrical properties of the material. Annealing of the samples at 600°C led to the recovery of transport in conduction band. The As, Ga and O implanted samples became semi-insulating, while the Si implanted samples were n-type. Carrier trapping times were short, shorter than 1 ps for the highest dose used. Models explaining the fast photocarrier decay are discussed.

11

Role of Arsenic Antisite Defect in Nonstoichiometric Gallium Arsenide

33%

Jasiński J., Kurpiewski A., Korοna K., Kamińska M., Ρalczewska M., Krotkus A., Marcinkievicius S., Liliental-Weber Z., Tan H. H., Jagadish C.

Acta Physica Polonica A

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1995

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vol. 88

|

issue 4

747-750

EN

Over the last few years there have been many studies of GaAs layers grown at low temperatures (180-300°C), so called LT GaAs. The interest in LT GaAs was motivated by the potential application of 600oC annealed LT GaAs in microwave and fast optoelectronic devices because of its short photocarrier lifetime, reasonable mobility and high resistivity. These properties are associated with the nonstoichiometry of LT GaAs. Recently, studies of comparable material, nonstoichiometric GaAs produced by arsenic ion implantation have been initiated. There is still a strong controversy as to whether the arsenic antisite (As_{Ga}) or arsenic precipitates are responsible for unique electrical properties of both materials. This paper presents the results of structural and electrical studies of high energy As implanted GaAs and comments on relationships between the structure and the resulting electrical properties.

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Grey Solitons in Saturable Media with Nonlinear Dispersion and Self-Frequency Shift

Bright and Dark Solitons in Generalized Kerr-Like Media

Recrystallization of Amorphous Layer in Ion Implanted GaAs - Transmission Electron Microscopy Studies

Antisites Defects in GaP

Investigation of Quantum Dot Structures Grown by MOCVD in InAs/GaAs System

Photo-ESR and Absorption Studies of Antisite Defects in GaP

Crystallographic Properties of Bulk GaN Crystals Grown at High Pressure

Defects Studies in As Grown and Neutron Irradiatcd Phosphorus Rich GaP

Interfacial Microstructure of Ni/Si-Based Ohmic Contacts To GaN

Ultrafast Carrier Trapping and High Resistivity of MeV Energy Ion Implanted GaAs

Role of Arsenic Antisite Defect in Nonstoichiometric Gallium Arsenide