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Low energy Ag ions were implanted into silicon and annealed at different temperatures in order to generate plasmonic active silicon hybrids. It was found that as the ion fluence of irradiation was increased, a monotonic decrease in the absorption spectra in the ultraviolet region occurs, due to amorphization and macrostructuring of the Si surface. At the same time, the optical spectra are characterized by a strong band after implantation presenting the contribution of the surface plasmon resonance (SPR) of Ag nanoparticles. After heat treatment at 500 and 600ºC, the SPR peak shifts to lower wavelengths, as compared to as implanted samples, whereas the plasmon position shifts to higher wavelengths for annealing at 700°C. This observation can be explained by either an out-diffusion of Ag or by stress relaxation and recrystallization of silicon. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45005]

In this work, a columnar structure of nickel thin film has been obtained using an advanced deposition technique known as Glancing Angle Deposition. Nickel thin film was deposited on glass sample at the constant emission current of 100 mA. Glass sample was positioned 15 degrees with respect to the nickel vapor flux. The obtained nickel thin film was characterized by Force Modulation Atomic Force Microscopy and by Scanning Electron Microscopy. Analysis indicated that the formation of the columnar structure occurred at the film thickness of 1 μm, which was achieved for the deposition time of 3 hours. [Projekat Ministarstva nauke Republike Srbije, br. III45005]

In this paper the results of an examination of the surface roughness and morphology dependence of silver thin films up to 100 nm thick deposited on a microscope glass on the deposition rate and on the deposition time are presented. It was found that, for a constant deposition rate, the surface roughness exhibits minimum at a certain layer thickness. This coincides with the turning point when the influence of the substrate surface on the deposition process becomes negligible, i.e., to the change in the nature of the system substrate/deposit from Ag/glass to Ag/Ag. For a constant layer thickness, sthe surface roughness minimum, achieved at a certain deposition rate, coincides to the turning point when the average free path for vertical adatom mobility becomes zero.

The role of defects on a substrate surface during the initial stages of nucleation and growth ofAg deposited electrochemically and physically on highly oriented pyrolytic graphite (HOPG) has been observed ex situ by scanning tunneling microscopy (STM). The silver was electrodeposited under current controlled electrochemical conditions at 26μA/cm2, which corresponded to a deposition rate of 0.1 monolayers (ML) per second. For comparison, physical deposition of Ag on HOPG was performed by DC Ar + ion sputtering, at the same deposition rate and for the same deposition times. In both cases, Ag grows in an island growth mode, but the distribution of the islands appears to be quite different. In physical deposition, the Ag islands are almost homogeneously distributed over the substrate surface and a slight accumulation of islands on steps does not contribut e significantly to the overallmorphology. This indicates the crucial role of point defects on the substrate in the initial stages of nucleation. In electrochemical deposition, more line d defects are observed after a flow of current, andtheir role in the beginning of the nucleat ion is more pronounced. Lined defects are responsible for the string-like shaped domains of deposited atoms. Also, the existence of string-like shaped nucleation exclusion zones is indicated. The problem of the formation of nucleation exclusion zones,which appear only in electrochemical deposition, has been reconsidered and a new explanaton of their formation is given. A mathematical model for the calculation of the radius of the nucleati on exclusion zone has been developed.

By combining the techniques of electrochemical slow potentiodynamic, AC impedance and atomic force microscopy (AFM), it was shown that the differences in the anodic dissolution rates of Al in 0.5 NaCl solutions as measured experimentally in the potential region between the corrosion and pitting potential, are mainly due to differences in surface roughness of the electrodes used. It was shown that mechanical grinding and polishing of the electrode surface with emery paper (400 grit) and alumina polishing powder (Ø 0.25 μm) can produce surfaces differing by a factor of 6 in the roughness factor Ra. By using AFM estimates of the roughness factors a true electrode capacitance of 4.63μC cm-2 and thickness dox ≈ 2.0 nm for the barrier layer of the surface film was estamited. The outer part of the film is porous, partly as amorphous Al(OH)3, or crystalline bayerite (Al2O3∙3H2O).

In pursuit of the ideal photocatalyst, cheap and stable semiconductor TiO2 is considered to be a good choice if one is able to reduce its band gap and decrease the recombination rate of charge carriers. The approach that offers such improvements for energy conversion applications is the modification of TiO2 with nitrogen and noble metals. However, the origin of these improvements and possibilities for further design of single-atom catalysts are not always straightforward. To shed light on the atomic-scale picture, we modeled the nitrogen-doped (001) anatase TiO2 surface as a support for palladium and platinum single-atom deposition. The thermodynamics of various synthesis routes for Pd/Pt deposition and nitrogen doping is considered based on density functional theory (DFT)-calculated energies, highlighting the effect of nitrogen doping on metal dimer formation and metal–support interaction. XPS analysis of the valence band of the modified TiO2 nanocrystals, and the calculated charge transfer and electronic structure of single-atom catalysts supported on the (001) anatase TiO2 surface provide an insight into modifications occurring in the valence zone of TiO2 due to nitrogen doping and Pd/Pt deposition at the surface. DFT results also show that substitutional nitrogen doping significantly increases metal–support interaction, while interstitial nitrogen doping promotes only Pt–support interaction. [ABSTRACT FROM AUTHOR]