Search results

1

Observation of Nickel Hydroxide Layer on Ni Electrode by in situ Atomic Force Microscopy

100%

Kowal A., Niewiara R., Perończyk B., Haber J.

Acta Physica Polonica A

|

1996

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vol. 89

|

issue 3

401-404

EN

The layer of nickel hydroxide was formed on the surface of polycrystalline Ni immersed in 1 M KOH by cycling the potential in the range between -0.1 and 0.6 V vs. Pt in 1 M KOH. The layer thickness of 8.5 nm, estimated by an electrochemical method, corresponded to about 10 monolayers of Ni(OH)_{2}. The changes of thickness of the nickel hydroxide film during the process of its oxidation and reduction were monitored by the use of in situ atomic force microscopy with the tip fixed and the electrode potential scanned between -0.1 and +0.6 V at a scan rate of 100 mV/s. The process of oxidation resulted in the film thickness decrease by about 3 nm. This change could be explained as to be due to the removal of a proton from Ni(OH)_{2} layer.

2

Reconstruction of the (001) Surface of Si from Molecular Dynamics

63%

Holender J., Jędrzejek C.

Acta Physica Polonica A

|

1991

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vol. 79

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issue 1

97-116

EN

The reconstruction of the (001) surface of Si at various temperatures is studied using molecular dynamics with many-body interactions. Two types of potentials were used: the Stillinger-Weber (SW), and Pearson and co-workers Axilrod-Teller type potential (AT). For Stillinger-Weber potential at low temperatures the (2x1) dimer reconstruction is about 0.07 eV per surface atom more preferable than the c(2x2)structure which is in agreement with the experimental reconstruction observed by STM. Contrary, for Axilrod-Teller type potential the c(2x2) structure is lower by 0.2 eV than the (2x1) structure. The silicon surface is stable up to 1500 K, all the dimers remain unbroken but some of them are tilted. The energies of various defects (suggested by STM studies) like single vacancy, two adjacent Si atoms vacancy, dimer vacancy, dimer vacancy with lower layer atoms rebonding and double dimer vacancy are estimated.

3

Reconstruction of the (001) Surface of Si from Molecular Dynamics

63%

Holender J. M., Jędrzejek C.

Acta Physica Polonica A

|

1991

|

vol. 79

|

issue 1

117-120

EN

The reconstruction of the (001) surface of Si at various temperatures is studied using molecular dynamics with many-body interactions. Two types of potentials were used: the Stillinger-Weber (SW), and Pearson and co-workers Axilrod-Teller type potential (AT). For Stillinger-Weber potential at low temperatures the (2x1) dimer reconstruction is about 0.07 eV per surface atom more preferable than the c(2x2)structure which is in agreement with the experimental reconstruction observed by STM. Contrary, for Axilrod-Teller type potential the c(2x2) structure is lower by 0.2 eV than the (2x1) structure. The silicon surface is stable up to 1500 K, all the dimers remain unbroken but some of them are tilted. The energies of various defects (suggested by STM studies) like single vacancy, two adjacent Si atoms vacancy, dimer vacancy, dimer vacancy with lower layer atoms rebonding and double dimer vacancy are estimated.

4

Crystallography of Boundaries and Interfaces

63%

Neumann W.

Acta Physica Polonica A

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1996

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vol. 89

|

issue 2

195-207

EN

The main crystallographic concepts of characterizing interface structures are treated and reviewed. It will be demonstrated in which way the approaches of interface crystallography can be used to analyse interface structures experimentally observed.

5

Defects in Detwinned LaGaO_{3} Substrates

63%

Mazur K., Fink-Finowicki J., Berkowski M., Schell N.

Acta Physica Polonica A

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1997

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vol. 92

|

issue 1

205-208

EN

Single crystals of lanthanum gallate would be the suitable substrate for YBaCuO films except for the phase transition and the tendency to twinning existing in this material. However, by appropriate choice of growth conditions in the Czochralski method, it is possible to grow single crystal of LaGaO_{3} with low density of twin boundaries. Special stress and temperature treatment can then be applied to such materials to remove majority of existing twins. The substrates were examined by X-ray topography before and after detwinning and the surface was scanned with a profilometer.

6

Ion Etching Effects Occurring in Secondary Ion Mass Spectrometry Depth profiling of InGaAs/InP and InGaAs/AlAs/InP MBE Grown Heterostructures

63%

Kozhukhov A., Konarski P., Herman M.

Acta Physica Polonica A

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1996

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vol. 90

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issue 5

869-874

EN

Depth profiling analysis of In_{x}Ga_{1-x}As heterolayers grown by MBE on Fe doped InP(100) substrates was performed in the SAJW-02 secondary ion mass spectrometry analyser equipped with 4.5 keV O_{2}^{+} ion source and a specially designed sample manipulator enabling depth profiling in the standard as well as in so-called Zalar rotation operation modes. The fairly high energy of the primary ion beam required for sputtering in secondary ion mass spectrometry measurements causes changes in surface topography, usually of different origin. Depth resolution parameters and roughness formation monitored by scanning electron microscopy were analysed for a set of samples with composition x changing in the range 0.33 to 0.60. The results were compared with the same data for a layer of x=0.53 (best lattice-matched to InP) grown on the top of a three monolayer thick AlAs film deposited previously on the InP substrate. Improvement in the depth profile resolution was revealed for the structure with an AlAs layer indicating sharper interface transition. Moreover, sample rotation applied for this structure improves further the depth profiling resolution. Thus, we showed for the first time that a very thin AlAs layer grown by MBE between the InP substrate and the In_{0.53}Ga_{0.47}As improves considerably the heterointerface properties and that Zalar rotation applied for depth profiling of the investigated material system diminishes further the negative effects of ion etching on depth resolution in secondary ion mass spectrometry analysis.

7

X-ray Diffraction Investigations of Structure of Silicon Single Crystals after Irradiation by Heavy Ions

63%

Auleytner J., Khrupa V., Datsenko L., Krasulya S., Skorokhod M.

Acta Physica Polonica A

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1996

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vol. 89

|

issue 3

301-307

EN

Structure distortions appearing near the surfaces of crystals irradiated by high energy ions (H, Kr, U) accelerated till energy of several MeV using respectively the accelerator U-120 (Kiev, Ukraine), the heavy ions accelerators (Caen, France and Darmstadt, Germany) were investigated by means of various X-ray diffraction methods (topography and diffractometry). Nonhomogeneous distribution of lattice distortions near the surfaces of irradiated crystals were discovered using these methods in all of the samples. Besides the barrier zones where the accelerated ions stopped, the wide distorted regions situated nearer the surface were found. The fine structure of different zones, their extents as well as the level of static Debye-Waller factor were determined. The depth distribution of this factor was compared with the results obtained by using the edge contrast measurements some years ago. This permitted us to draw conclusions about some relaxation of elastic strains in the interference regions after many years.

8

Reconstruction of Tungsten (111) and (211) Surfaces Induced by Carbon and Oxygen

63%

Szczudlo Z., Zuber S., Szczepkowicz A., Ciszewski A.

Acta Physica Polonica A

|

2002

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vol. 102

|

issue 6

781-784

EN

Scanning tunneling microscopy is used to obtain images of reconstructed W(111) and W(211) surfaces. The reconstruction is induced by submonolayer coverages of carbon and oxygen.

9

Surface of BiSrCaCuO Single Crystal Observed by Means of Scanning Tunneling Microscope

51%

Witek A., Reich A., Czajka R., Pajączkowska A., Rauluszkiewicz J.

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issue 5

717-722

EN

The topographic images of a Bi_{0.7}Pb_{0.3}SrCaCu_{1.8}O_{x} single crystal were studied by means of the scanning tunneling microscope. The structure of terraces and steps seen on the surface reflects the crystallographic structure of bulk.

10

Structure and Relative Stability of Si_n (n=10-16) Clusters

51%

Mahtout S., Belkhir M.

Acta Physica Polonica A

|

2006

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vol. 109

|

issue 6

685-693

EN

Ab initio molecular dynamics simulated annealing technique coupled with density functional theory in the local density approximation implemented in Spanish initiative for electronic simulations with thousands of atoms method is employed to search the ground state geometries of silicon clusters containing 10-16 atoms. We found a number of new isomers which are not previously reported. The atoms in all these clusters exhibit pronounced preference for residing on the surface. The binding energies increase while the highest occupied-lowest unoccupied molecular orbital gap generally decreases with the increase in clusters size.

11

Near Field Optical Microscopy and Spectroscopy with STM and AFM Probes

51%

Bergossi O., Bachelot R., Wioland H., Wurtz G., Laddada R., Adam P., Bijeon J., Royer P.

Acta Physica Polonica A

|

1998

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vol. 93

|

issue 2

393-398

EN

This article deals with a new generation of scanning near field optical microscopes (SNOM), called apertureless SNOM, based on metallic, semi-conductive or dielectric probes. The classification of the apertureless probe among the usual SNOM probes is discussed in the first part. Then, we present the different apertureless SNOM configurations that we develop, with various commercial AFM and home-made tungsten tips, and several illumination and collection modes. Finally, after a preliminary result in near field imaging, we propose a promising application of such microscopes dedicated to the near field fluorescence spectroscopy.

12

High Quality (100) and (001) Oriented Substrates Prepared from Czochralski Grown SrLaGaO_{4} and SrLaAlO_{4} Single Crystals

51%

Berkowski M., Fink-Finowicki J., Sass J., Mazur K.

Acta Physica Polonica A

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1997

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vol. 92

|

issue 1

201-204

EN

The growth of SrLaGaO_{4} and SrLaAlO_{4} crystals on ⟨100⟩ and ⟨001⟩ oriented seeds was investigated. Various defects, which appeared in crystals grown on these two orientations, were observed in polarized light and by X-ray diffraction topography. It was found that to obtain a substrate of the best quality, the crystal should be cut along the growth directions. Therefore, crystals pulled along ⟨100⟩ direction are utilized for preparation of (001) substrates, whereas (100) substrates are better to cut from crystals grown on ⟨001⟩ seed. The quality of the prepared substrates was determined by high resolution X-ray diffraction study in terms of rocking curve and mean mosaic angle.

13

Comparative Studies of Surface Roughness of Thin Epitaxial Si Films by Computer Simulations and Experimental X-Ray and Optical Methods

51%

Żymierska D., Auleytner J., Domagała J., Szewczyk A., Dmitruk N.

Acta Physica Polonica A

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1997

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vol. 91

|

issue 5

1025-1030

EN

The paper presents investigations of the surface roughness of epitaxial silicon films obtained by chemical vapour deposition with chloric and MOCVD processes. The flat surfaces of films and chemically etched surfaces of substrates were studied by optical methods as well as by X-ray reflectivity at grazing incidence. The computer simulations based on Fresnel theory were compared with the experimental results.

14

STM/AFM Images and Tunneling Spectra of Nd_{2-x}Ce_{x}CuO_{4-y} Single Crystals

51%

Susła B., Sadowski W., Klimczuk T., Czajka R.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 1

209-214

EN

The results of the scanning tunneling microscopy and spectroscopy as well as atomic force microscopy measurements on the Nd_{2-x}Ce_{x}CuO_{4-y} single crystals in ambient conditions are reported. Using the scanning tunneling microscopy we were able to modify the Nd_{2-x}Ce_{x}CuO_{4-y} ab-plane in air under the conditions of sample bias voltage V_{t}=500 mV and set current I_{s}=0.3 nA. It is possible to prepare atomically flat and clean surfaces as well as to create new structures in a nanometer scale in these electron-doped materials. The similar processes were not observed during atomic force microscopy imaging.

15

Nucleation and Crystal Growth of Cu on Ir Tips Under Ultra-High Vacuum and in the Presence of Oxygen

51%

Zuber S., Ciszewski A.

Acta Physica Polonica A

|

2000

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vol. 97

|

issue 4

681-692

EN

Results concerning the morphology of Cu adsorption layers deposited from vapor under ultrahigh vacuum on Ir tip and the influence of oxygen on this morphology are reported. The method employed was field electron emission microscopy. It was found that the presence of oxygen decreases the copper wettability of iridium. Preadsorption of oxygen on the Ir surface is followed by an increase in cohesion interaction between atoms of the Cu deposited onto the tip at room temperature. Coadsorption of Cu and O on the Ir tip surface at liquid nitrogen temperature, when followed by gradually heating the adlayer, results in crystallization of the deposit in the temperature range from 430 K to about 700 K. Some evidence indicates the formation of Cu_{2}O with a high degree of crystallinity under these conditions. Cu and O coadsorption on the Ir surface at a temperature higher than 1090 K leads to selective accumulation of Cu on the {111} faces and to formation of epitaxial crystals which are oriented to the substrate in the same manner as the Cu crystals grown at ultra-high vacuum from Cu flux containing no oxygen. Oxygen incorporated into the Cu beam interact preferentially with {011} and {001} Ir faces, where it can produce oxide layers.

16

Superconducting Lead Granular Layer Prepared by Reducing in Hydrogen Lead of Germanate Glasses

51%

Gackowska J., Gazda M., Trzebiatowski K., Kusz B.

Acta Physica Polonica A

|

2006

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vol. 109

|

issue 4-5

591-596

EN

The thin layer of Pb granules on the surface of the lead-germanate glass was prepared by thermal annealing in hydrogen. The structure and superconducting properties of lead layer depend on temperature and time of reduction. The influence of time and temperature of reduction on the properties of the reduced layer thickness has been studied.

17

Surface Roughness by X-ray and Neutron Scattering Methods

51%

Sinha S.

Acta Physica Polonica A

|

1996

|

vol. 89

|

issue 2

219-234

EN

We discuss how the roughness and morphology of surfaces and interfaces can be characterized by the nondestructive techniques of X-ray and neutron scattering. We first discuss the mathematical description of rough surfaces in terms of correlation functions and then discuss the various kinds of rough surfaces which exist. These fall into the category of self-affine (Gaussian) surfaces, surfaces with capillary wave fluctuations, stepped surfaces, and surfaces with islands or pits. We then discuss how the scattering from such surfaces may be described and which types of information are available from specular reflectivity, off-specular (diffuse) scattering, and grazing incidence reflection experiments, including a comparison with results obtained by other surface techniques. We then discuss multiple rough interfaces and the scattering from thin films and multilayers. Finally, we shall discuss scattering of neutrons by magnetically rough surfaces and multilayers.

18

Review of Surface Relaxation and Reconstruction Phenomena

51%

Zieliński P.

Acta Physica Polonica A

|

1996

|

vol. 89

|

issue 2

251-263

EN

The basic definitions concerning structure of surface are given. The principal experimental methods of the observation of surfaces are reviewed. A possibly heuristic explanation is given of principal theoretical concepts underlying the present understanding of the surface phenomena. The best known and/or understood examples of the surface relaxation, surface reconstruction and roughening are reviewed.

19

Crystallization of Amorphous Ribbon Observed by Means of Scanning Tunneling Microscope

51%

Witek A., Reich A., Raułuszkiewicz J., Zych W.

Acta Physica Polonica A

|

1993

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vol. 83

|

issue 4

463-467

EN

Surfaces of amorphous ribbon Fe70V10 B20 were observed by means of the scanning tunneling microscope before and after the annealing in vacuum. The topographic images of the air-side surfaces after annealing are similar in the x-y plane and different in the z-direction. From the scanning tunnelling microscope images some information on the crystallization of amorphous ribbons can be deduced.

20

X-Ray Diffraction Investigations of NdGaO_{3} Single Crystal

51%

Mazur K., Sass J., Giersz W., Reiche P., Schell N.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 1

226-230

EN

Neodymium gallium perovskite single crystals grown with the Czochralski method were examined with several complementary X-ray methods. By means of X-ray diffraction topography and reciprocal space diagram the structural perfection and crystal homogeneity of the studied wafers were determined. Additionally, the results of the X-ray reflectometry investigations of the surface perfection after the mechanochemical treatment are presented.

Refine search results

Observation of Nickel Hydroxide Layer on Ni Electrode by in situ Atomic Force Microscopy

Reconstruction of the (001) Surface of Si from Molecular Dynamics

Reconstruction of the (001) Surface of Si from Molecular Dynamics

Crystallography of Boundaries and Interfaces

Defects in Detwinned LaGaO_{3} Substrates

Ion Etching Effects Occurring in Secondary Ion Mass Spectrometry Depth profiling of InGaAs/InP and InGaAs/AlAs/InP MBE Grown Heterostructures

X-ray Diffraction Investigations of Structure of Silicon Single Crystals after Irradiation by Heavy Ions

Reconstruction of Tungsten (111) and (211) Surfaces Induced by Carbon and Oxygen

Surface of BiSrCaCuO Single Crystal Observed by Means of Scanning Tunneling Microscope

Structure and Relative Stability of Si_n (n=10-16) Clusters

Near Field Optical Microscopy and Spectroscopy with STM and AFM Probes

High Quality (100) and (001) Oriented Substrates Prepared from Czochralski Grown SrLaGaO_{4} and SrLaAlO_{4} Single Crystals

Comparative Studies of Surface Roughness of Thin Epitaxial Si Films by Computer Simulations and Experimental X-Ray and Optical Methods

STM/AFM Images and Tunneling Spectra of Nd_{2-x}Ce_{x}CuO_{4-y} Single Crystals

Nucleation and Crystal Growth of Cu on Ir Tips Under Ultra-High Vacuum and in the Presence of Oxygen

Superconducting Lead Granular Layer Prepared by Reducing in Hydrogen Lead of Germanate Glasses

Surface Roughness by X-ray and Neutron Scattering Methods

Review of Surface Relaxation and Reconstruction Phenomena

Crystallization of Amorphous Ribbon Observed by Means of Scanning Tunneling Microscope

X-Ray Diffraction Investigations of NdGaO_{3} Single Crystal