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1

Thermal Desorption of Au from W(001) Surface

100%

Błaszczyszyn R., Chrzanowski J., Godowski P.

Acta Physica Polonica A

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2002

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vol. 102

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issue 6

785-794

EN

Adsorption of Au on W(001) at 450 K up to multilayer structures was investigated. Temperature programmed desorption technique was used in determination of coverage dependent desorption energy (region up to one monolayer). Results were discussed in terms of competitive interactions of Au-Au and Au-W atoms. Simple procedure for prediction of faceting behavior on the interface, basing on the desorption data, was postulated. It was deduced that the Au/W(001) interface should not show faceting tendency after thermal treatment.

2

Variable Temperature STM/STS Investigations of Ag Nanoparticles Growth on Semiconductor Surfaces

100%

Suto S., Czajka R., Szuba S., Shiwa A., Winiarz S., Nagashima H., Kato H., Yamada T., Kasuya A.

Acta Physica Polonica A

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2003

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vol. 104

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issue 3-4

289-302

EN

We have investigated the growth of Ag nanoparticles deposited on Si(111), H/Si(111)-(1×1) and Bi_2Te_3 substrates using a variable temperature scanning tunneling microscopy. These substrates are different as regards the model system for cluster and islands growth at the nanometer scale. Ag was evaporated onto the sample mounted at the scanning tunneling microscopy stage in vacuum of 10^{-10} Torr range during evaporation. The substrates were kept at different temperatures: -150˚C, room temperature, and 300˚C during the deposition process. In general, we have observed 3D growth mode up to several ML coverage. The density of clusters and their size were functions of the substrate's temperature during the deposition process - a higher density and a smaller size at -150˚C were in opposition to the 300˚C results - a lower density and a larger size. Low temperature depositions led to continuous layers above 10 ML coverage but the surface was covered by small Ag clusters of 1-2 nm in heights and 2-3 nm in diameters. The log-log graphs of height and projected diameter of Ag clusters revealed different slopes indicating different growth mechanisms at low and high temperatures. We obtained the value of n=0.25±0.02, typical of the so-called droplet model of cluster growth, only at 300˚C. Scanning tunneling spectroscopy measurements revealed clearly different I-V (and dI/dV vs. bias voltage) curves measured above clusters and directly above the substrate. In discussion, we compared our results to theoretically calculated density of states from other papers, finding conformity for partial density of states.

3

Adsorption Properties of the Cu(115) Surface: Basic Interfaces

100%

Godowski P., Groso A., Hoffmann S., Onsgaard J.

Acta Physica Polonica A

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2010

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vol. 117

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issue 6

928-935

EN

The interfaces: K/Cu(115) and CO/Cu(115) have been characterized using surface sensitive techniques, including low energy electron diffraction and photoelectron spectroscopy. K adatoms show tendency to occupy the sites close to the step edges. At low temperature (near 125 K), after completion of two layers, potassium grows in 3D islands (the Stranski-Krastanov mode). At higher temperature, e.g. at room temperature, potassium introduces reconstruction of the substrate even at low coverages. Calibration of the alkali coverage, up to completion of the first layer, using the work function changes curve has been confirmed as a very convenient and precise procedure. The adsorbed state of CO at 130 K has been identified by registration of core levels obtained by the use synchrotron radiation photoelectron spectroscopy. The characteristics of the main 1s and satellite peaks have been analyzed in context of substrate geometry and compared with the ones of other copper planes. There are no indications of dissociative adsorption of CO, only residual carbon and oxygen were found after adsorbate desorption around 220 K. CO molecules show a strong tendency to "on top" adsorption in sites far from the step edges of the Cu(115) surface.

4

STM/STS Studies of the Structural Phase Transition in the Growth of Ultra-Thin Bi Films on Si(111)

100%

Sadowski J., Nagao T., Saito M., Oreshkin A., Yaginuma S., Hasegawa S., Ohno T., Sakurai T.

Acta Physica Polonica A

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2003

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vol. 104

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issue 3-4

381-387

EN

Growth of thin metal films on semiconductors has been always an important subject for extensive experimental and theoretical studies. As the applicability of well-ordered nanostructures in electronic applications depends strongly on their size and distribution, it is necessary to understand the processes that govern the growth of such structures. In this paper we present the results of investigation of the room temperature growth of thin Bi film on Si(111). In our study we clarified that rotationally disordered, pseudo-cubic Bi(012) islands with uniform height of ≈13Å are formed in the initial stage of Bi film growth. With increase in the amount of bismuth on the surface, islands interconnect maintaining however their uniform height. This process is further accompanied by the unique and unexpected structural phase transition of the Bi(012) film into a hexagonal Bi(001) film.

5

Amorphous Carbon Thin Films Deposited on Si and PET: Study of Interface States

100%

Mariazzi S., Macchi C., Karwasz G., Brusa R., Laidani N., Bartali R., Gottardi G., Anderle M.

Acta Physica Polonica A

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2005

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vol. 107

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issue 5

842-847

EN

Thin carbon films with various thicknesses, deposited on different substrates (Si and poly-ethylene-terephthalate) at the same operating conditions in a radio frequency plasma enhanced chemical vapour deposition system were characterized by Doppler broadening spectroscopy. The films and the substrates were depth profiled by a slow positron beam. The aim of these measurements was to study the open volume structure and the interface of the films. It was found that, independently from the substrate, the films were homogeneous and exhibited the same open volume distribution. On the contrary, the effective positron diffusion length in the Si substrate was found to change with the thickness of the carbon films. This behaviour was interpreted as a change in the electric field at the carbon/silicon interface.

6

Effect of Hydrostatic Pressure on Photoluminescence Spectra from Structures with Si Nanocrystals Fabricated in SiO_2 Matrix

100%

Zhuravlev K., Tyschenko I., Vandyshev E., Bulytova N., Misiuk A., Rebohle L., Skorupa W.

Acta Physica Polonica A

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2002

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vol. 102

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issue 2

337-344

EN

The effect of hydrostatic pressure applied at high temperature on photoluminescence of Si-implanted SiO_2 films was studied. A "blue"-shift of PL spectrum from the SiO_2 films implanted with Si^+ ions to total dose of 1.2×10^{17} cm^{-2} with an increase in hydrostatic pressure was observed. For the films implanted with Si^+ ions to a total dose of 4.8×10^{16} cm^{-2} high temperature annealing under high hydrostatic pressure (12 kbar) causes a "red"-shift of photoluminescence spectrum. The "red" photoluminescence bands are attributed to Si nanocrystals while the "blue" ones are related to Si nanocrystals of reduced size or chains of silicon atoms or ≡Si-Si≡ defects. A decrease in size of Si nanocluster size occurs in result of the pressure-induced decrease in the diffusion of silicon atoms.

7

Surface Electronic Properties of Fe Nanoparticles on c(2×2)-N/Cu(001)

88%

Getzlaff M., Bode M., Wiesendanger R.

Acta Physica Polonica A

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2003

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vol. 104

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issue 3-4

327-335

EN

We prepared nanoscaled particles consisting of ferromagnetic material on a nanostructured template. This nanolithographic procedure allows to fabricate high-density magnetic nanodots in a highly ordered way. For this purpose, Fe particles were grown on the c(2×2)-N/Cu(001) surface which exhibits a checkerboard-like structure. Scanning tunneling spectroscopic measurements demonstrate that the electronic properties of the areas with deposited material are identical to clean copper. Fe nanoparticles on the reconstructed patches show a significantly different electronic behavior. These observations directly hint to a covering of iron with copper on the clean surface.

8

Thermodynamic model of crystallization and melting of small particles

51%

Samsonov V., Malkov O.

Open Physics

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2004

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vol. 2

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issue 1

90-103

EN

The size dependence of the nanocrystal melting temperature has been investigated based on a nonequilibrium thermodynamics approach. An expression has been derived for the melting temperature that, contrary to the classical Tomson formula, takes into account the metastable character of the crystal nucleus-melt shell equilibrium. Quantitative estimations have been carried out for small spherical particles of aluminum, tin, and lead.

Refine search results

Thermal Desorption of Au from W(001) Surface

Variable Temperature STM/STS Investigations of Ag Nanoparticles Growth on Semiconductor Surfaces

Adsorption Properties of the Cu(115) Surface: Basic Interfaces

STM/STS Studies of the Structural Phase Transition in the Growth of Ultra-Thin Bi Films on Si(111)

Amorphous Carbon Thin Films Deposited on Si and PET: Study of Interface States

Effect of Hydrostatic Pressure on Photoluminescence Spectra from Structures with Si Nanocrystals Fabricated in SiO_2 Matrix

Surface Electronic Properties of Fe Nanoparticles on c(2×2)-N/Cu(001)

Thermodynamic model of crystallization and melting of small particles