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1

High Resistivity AlGaAs Grown by Low Temperature MBE

100%

Radomska D., Ratajczak J., Regiński K., Bugajski M.

Acta Physica Polonica A

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1998

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vol. 94

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issue 3

492-496

EN

Al_{0.3}Ga_{0.7}As layers were grown by molecular beam epitaxy using substrate temperature 200-300°C, tetrameric As and two values of As/Ga+Al flux ratio i.e. 3 or 8. The post-growth annealing was performed in situ at 600°C for 20 min under As-overpressure. The samples were characterised by reflection high-energy electron diffraction, transmission electron microscope and room-temperature I-V measurements of n^{+}/LT grown layer /n^{+} resistors. The resistivity and trap-filled limited voltage have been determined. The best layers exhibited ρ of the order of 10^{9} Ω cm, were monocrystalline, uniformly precipitated and without dislocations.

2

Effect of Secondary Electroluminescence on Cathodoluminescence and Other Luminescence Measurements

88%

Pluska M., Czerwinski A., Szerling A., Ratajczak J., Kątcki J.

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vol. 125

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issue 4

1027-1032

EN

Cathodoluminescence and photoluminescence measurements are commonly accepted as revealing local properties of a specimen region excited by a beam of electrons or photons. However, in the presence of a strong electric field (e.g. a junction) an electron (or light/laser) beam-induced current is generated, which spreads over the structure. A secondary non-local electroluminescence, generated by this current and detected together with the expected luminescence signal, may strongly distort measurement results. This was confirmed by cathodoluminescence measurements on test structures prepared by focused ion beam on AlGaAs/GaAs/InGaAs laser heterostructures. Methods for minimizing the distortion of measured luminescence signals are presented.

3

Dependence of Nanoelectronic-Structure Defect Detection by Cathodoluminescence on Electron Beam Current

88%

Pluska M., Czerwinski A., Ratajczak J., Szerling A., Kątcki J.

Acta Physica Polonica A

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2009

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vol. 116

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issue S

S-86-S-88

EN

The dependence of defect detection by cathodoluminescence in a scanning electron microscope on the electron beam current is considered. The examined specimens are AlGaAs/GaAs laser heterostructures with InGaAs quantum well. It is shown that for low electron beam currents, which are typically used, the uniform cathodoluminescence is observed, while for the increasing high electron beam current the oval defects become more and more visible. The influence of electrical properties of the structure on the luminescence detection is explained.

4

Whisker Growth in Tin Alloys on Glass-Epoxy Laminate Studied by Scanning Ion Microscopy and Energy-Dispersive X-Ray Spectroscopy

88%

Czerwiński A., Skwarek A., Płuska M., Ratajczak J., Witek K.

Archives of Metallurgy and Materials

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2013

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issue 2

5

Oxygen Precipitation in Si:O Annealed under High Hydrostatic Pressure

76%

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.

6

Response of ZnO/GaN Heterostructure to Ion Irradiation

64%

Barcz A., Pągowska K., Kozubal M., Guziewicz E., Borysiewicz M., Dyczewski J., Jakieła R., Ratajczak J., Snigurenko D., Dynowska E.

Acta Physica Polonica A

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2015

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vol. 128

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issue 5

832-835

EN

In this paper we report on the analysis of Al⁺-implanted ZnO/GaN bilayers in search for the damage production mechanism and possible ion mixing. 100 nm or 200 nm thick ZnO epitaxial layers were grown on GaN substrates by either sputter deposition or atomic layer deposition technique followed by adequate annealing. Ion irradiations of ZnO/GaN were carried out at room temperature using 200 keV Al⁺ ions with fluences of 2×10¹⁵ and 10¹⁶ at./cm². Unprocessed and irradiated samples were characterized by the Rutherford backscattering spectrometry in channeling geometry (RBS\c), X-ray diffraction and transmission electron microscopy. Additionally, secondary ion mass spectrometry was employed for the aforementioned samples as well as for the implanted samples subjected to further annealing. It was found that the damage distributions in ZnO/GaN differ considerably from the corresponding defect profiles in the bulk ZnO and GaN crystals, most probably due to an additional strain originating from the lattice mismatch. Amount of intermixing appears to be relatively small; apparently, efficient recombination prevents foreign atoms to relocate to large distances.

7

TEM Characterization of Polysilicon and Silicide Fin Fabrication Processes of FinFETs

64%

Ratajczak J., Łaszcz A., Czerwinski A., Kątcki J., Tang X., Reckinger N., Yarekha D., Larrieu G., Dubois E.

Acta Physica Polonica A

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2009

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vol. 116

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issue S

S-89-S-91

EN

The transmission electron microscopy characterization of various silicon and silicide fin structures intended for application in FinFET devices has been performed. The results showed that transmission electron microscopy is a very useful tool for optimization of manufacturing processes of fin nanostructures in FinFETs.

8

The migration of bone marrow-derived non-hematopoietic tissue-committed stem cells is regulated in an SDF-1-, HGF-, and LIF-dependent manner

64%

Kucia M., Wojakowski W., Reca R., Machalinski B., Gozdzik J., Majka M., Baran J., Ratajczak J., Ratajczak M. Z.

Archivum Immunologiae et Therapiae Experimentalis

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2006

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vol. 54

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issue 2

121-135

EN

Introduction: Recently we identified in bone marrow (BM) by employing chemotactic isolation to SDF-1 gradient combined with real time RT-PCR analysis a mobile population of CXCR4+ BM mononuclear cells that express mRNA for various markers of early tissue-committed stem cells (TCSCs). In this study we evaluated whether TCSCs respond to other moto-morphogens, such as hepatocyte growth factor (HGF) and leukemia inhibitory factor (LIF). Materials and Methods: We again employed chemotactic isolation combined with real-time RT-PCR analysis to assess whether murine and human BM contain TCSCs that respond to HGF and LIF gradients. We also evaluated expressions of HGF and LIF in damaged organs. Results: We noted that the number of TCSCs is highest in BM from young (1- to 2-month-old) mice and decreases in 1-year-old animals. Murine and human TCSCs 1) respond to HGF and LIF gradients in addition to an SDF-1 gradient, 2) reside in populations of BM-derived non-hematopoietic CD45? cells, and 3) are released (mobilized) from BM into the peripheral blood (PB) during tissue injury (e.g. after partial body irradiation). Conclusions: These findings further support our theory of the BM as a ?hideout' for TCSCs and we suggest that their presence in BM tissue should be considered before experimental evidence is interpreted simply as transdifferentiation/plasticity of hematopoietic stem cells. Since we demonstrated that not only SDF-1, but also HGF and LIF are upregulated in damaged tissues, we postulate that CXCR4+ c-Met+ LIF-R+ TCSC could be mobilized from the BM into the PB, from which they are subsequently chemoattracted to damaged organs, where they play a role in tissue repair/regeneration.

9

Ultrathin NbN Films for Superconducting Single-Photon Detectors

52%

Słysz W., Guziewicz M., Borysiewicz M., Domagała J., Pasternak I., Hejduk K., Rzodkiewicz W., Ratajczak J., Bar J., Węgrzecki M., Grabiec P., Grodecki R., Węgrzecka I., Sobolewski R.

Acta Physica Polonica A

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2011

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vol. 120

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issue 1

200-203

EN

We present our research on fabrication and structural and transport characterization of ultrathin superconducting NbN layers deposited on both single-crystal Al_2O_3 and Si wafers, and SiO_2 and Si_3N_4 buffer layers grown directly on Si wafers. The thicknesses of our films varied from 6 nm to 50 nm and they were grown using reactive RF magnetron sputtering on substrates maintained at the temperature 850°C. We have performed extensive morphology characterization of our films using the X-ray diffraction method and atomic force microscopy, and related the results to the type of the substrate used for the film deposition. Our transport measurements showed that even the thinnest, 6 nm thick NbN films had the superconducting critical temperature of 10-12 K, which was increased to 14 K for thicker films.

10

Technology of Ultrathin NbN and NbTiN Films for Superconducting Photodetectors

52%

Guziewicz M., Slysz W., Borysiewicz M., Kruszka R., Sidor Z., Juchniewicz M., Golaszewska K., Domagala J., Rzodkiewicz W., Ratajczak J., Bar J., Wegrzecki M., Sobolewski R.

Acta Physica Polonica A

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2011

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vol. 120

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issue 6A

A-76-A-79

EN

We report fabrication and characterization of ultrathin NbN and NbTiN films designed for superconducting photodetectors. Our NbN and NbTiN films were deposited on Al_2O_3 and Si single-crystal wafers by a high-temperature, reactive magnetron sputtering method and, subsequently, annealed at 1000°C. The best, 18 nm thick NbN films deposited on sapphire exhibited the critical temperature of 15.0 K and the critical current density as high as ≈ 8 × 10^6 A/cm^2 at 4.8 K.

Refine search results

High Resistivity AlGaAs Grown by Low Temperature MBE

Effect of Secondary Electroluminescence on Cathodoluminescence and Other Luminescence Measurements

Dependence of Nanoelectronic-Structure Defect Detection by Cathodoluminescence on Electron Beam Current

Whisker Growth in Tin Alloys on Glass-Epoxy Laminate Studied by Scanning Ion Microscopy and Energy-Dispersive X-Ray Spectroscopy

Oxygen Precipitation in Si:O Annealed under High Hydrostatic Pressure

Response of ZnO/GaN Heterostructure to Ion Irradiation

TEM Characterization of Polysilicon and Silicide Fin Fabrication Processes of FinFETs

The migration of bone marrow-derived non-hematopoietic tissue-committed stem cells is regulated in an SDF-1-, HGF-, and LIF-dependent manner

Ultrathin NbN Films for Superconducting Single-Photon Detectors

Technology of Ultrathin NbN and NbTiN Films for Superconducting Photodetectors