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Surface diffusion and cluster formation of gold on the silicon (111)

Plechystyy V., Shtablavyi I., Rybacki K., Winczewski S., Mudry S., Rybicki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 101, nr 2

49--59

EN

Purpose: Investigation of the gold atoms behaviour on the surface of silicon by molecular dynamics simulation method. The studies were performed for the case of one, two and four atoms, as well as incomplete and complete filling of gold atoms on the silicon surface. Design/methodology/approach: Investigations were performed by the method of molecular dynamics simulation using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). MEAM potential of interatomic interaction was used for modelling. Molecular dynamic simulations were carried out in isothermal-isobaric ensemble (NpT) with a timestep 1.0 fs. Findings: As a result of studies, the preferred interaction between gold atoms and the formation of clusters at temperatures up to 800 K was revealed. Analysis of the temperature dependences of the number of large jumps of atoms made it possible to calculate the activation energy of a single jump. It was found that activation energy of single atomic displacement decreases with increasing number of gold atoms. Research limitations/implications: Only a limited number of sets of atoms were used in the study. It is possible that for another combination of atoms and a larger substrate surface, the formation of gold nanoislands on the silicon surface can be observed, which requires further research. Practical implications: The research results can be used to select the modes of gold sputtering to create gold nanoislands or nanopillars on the silicon surface. Originality/value: Computer modelling of the behaviour of gold atoms on the surface of silicon with the possibility of their self-organization and cluster formation was performed for the first time.

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Hydrogen atoms at the palladium surface, at the MgO surface and at the Pd-MgO metal-support boundary. Towards computer modelling of the spillover effect

Bartczak W.M., Stawowska J.

Materials Science Poland

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2006

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Vol. 24, No. 2/1

421--432

EN

The work is devoted to computer modelling of interactions of atomic hydrogen with palladium and MgO surfaces, and with Pd atoms adsorbed on MgO surface. Quantum calculations were performed using the methods of the Density Functional Theory (DFT) with gradient-corrected functionals for electron exchange and correlation. The potential energy surfaces were calculated for a hydrogen atom interacting with Pd and MgO surfaces. The results indicate an easy (0.17 eV activation barrier) diffusion of hydrogen atoms over the metal surface. A possibility of migration of H atoms from the metal surface onto the MgO support surface (the "spillover effect") is discussed. It was found that the transfer of a hydrogen atom from the vicinity of a Pd atom to O sites of the MgO surface results in the energy gain of the order of 0.5 eV. The transfer, however, is an activated process with the activation energy about 0.8 eV.

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XLI Szkoła Zimowa w Karpaczu [Ze zjazdów i konferencji]

Pękalski A., Szwabiński J.

Postępy Fizyki

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2005

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T. 56, z. 4

181-181

PL

W dniach 6-12 lutego 2005 r. odbyła się w Lądku Zdroju XLI Zimowa Szkoła Fizyki Teoretycznej, zorganizowana przez Instytut Fi-zyki Teoretycznej Uniwersytetu Wrocławskiego, Komitet Fizyki PAN oraz Polską Akademię Umiejętności w Krakowie. Tematyką Szkoły była dyfuzja powierzchniowa oraz fizyka materiałów granulowanych.

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Analiza kinetyki adsorpcji przy zmiennym współczynniku dyfuzji powierzchniowej

Georgiou A., Kupiec K.

Inżynieria Chemiczna i Procesowa

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2004

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T. 25, z. 3/1

877-882

PL

Przedstawiono przybliżony model adsorpcji w ziarnie dla przypadku, gdy współczynnik dyfuzji powierzchniowej zmienia się ze stężeniem. Model z powodzeniem zastosowano do wyznaczenia stałej czasowej dyfuzji dla danych eksperymentalnych znalezionych w literaturze.

EN

A new approximate model for adsorption with concentration dependent surface diffusivity in a single particle is derived. The new model is applied to analyze experimental from the literature and it is shown that can be successfully applied in the determination of kinetic parameters.