Diffusion induced atomic islands on the surface of Ni/Cu nanolayers

K

On the formation of blisters in annealed hydrogenated a-Si layers

Differently hydrogenated radio frequency-sputtered a-Si layers have been studied by infrared (IR) spectroscopy as a function of the annealing time at 350 Celsius with the aim to get a deeper understanding of the origin of blisters previously observed by us in a-Si/a-Ge multilayers prepared under the same conditions as the ones applied to the present a-Si layers. The H content varied between 10.8 and 17.6 at.% as measured by elastic recoil detection analysis. IR spectroscopy showed that the concentration of the clustered (Si-H)n groups and of the (Si-H2)n (n ≥ 1) polymers increased at the expense of the Si-H mono-hydrides with increasing annealing time, suggesting that there is a corresponding increase of the volume of micro-voids whose walls are assumed from literature to be decorated by the clustered mono-hydride groups and polymers. At the same time, an increase in the size of surface blisters was observed. Also, with increasing annealing time, the total concentration of bonded H of any type decreases, indicating that H is partially released from its bonds to Si. It is argued that the H released from the (Si-H)n complexes and polymers at the microvoid surfaces form molecular H2 inside the voids, whose size increases upon annealing because of the thermal expansion of the H2 gas, eventually producing plastic surface deformation in the shape of blisters

Enhanced physicochemical and biological properties of ion-implanted Titanium using Electron Cyclotron Resonance ion sources

The surface properties of metallic implants play an important role in their clinical success. Improving upon the inherent shortcomings of Ti implants, such as poor bioactivity, is imperative for achieving clinical use. In this study, we have developed a Ti implant modified with Ca or dual Ca + Si ions on the surface using an electron cyclotron resonance ion source (ECRIS). The physicochemical and biological properties of ion-implanted Ti surfaces were analyzed using various analytical techniques, such as surface analyses, potentiodynamic polarization and cell culture. Experimental results indicated that a rough morphology was observed on the Ti substrate surface modified by ECRIS plasma ions. The in vitro electrochemical measurement results also indicated that the Ca + Si ion-implanted surface had a more beneficial and desired behavior than the pristine Ti substrate. Compared to the pristine Ti substrate, all ion-implanted samples had a lower hemolysis ratio. MG63 cells cultured on the high Ca and dual Ca + Si ion-implanted surfaces revealed significantly greater cell viability in comparison to the pristine Ti substrate. In conclusion, surface modification by electron cyclotron resonance Ca and Si ion sources could be an effective method for Ti implants

Szilárdtest-reakciók nanoskálán

K

Investigation of the Performance of Thermally Generated Au/Ag Nanoislands for SERS and LSPR Applications

L

Application of Surface Roughness Data for the Evaluation of Depth Profile Measurements of Nanoscale Multilayers

A secondary neutral mass spectrometric (SNMS) depth profile study of electrodeposited Co/Cu multilayers was performed. Depth profile measurements were performed both in the conventional way (i.e., starting the sputtering from the final deposit surface) and in the reverse manner (i.e., detaching the multilayers from the substrate and starting the analysis from the substrate side, which was very smooth as compared to the final deposit surface). The latter method could yield significantly larger intensity fluctuations in the SNMS spectra. Surface roughness data were measured with atomic force microscopy (AFM) for multilayers with different bilayer numbers but otherwise exhibiting the same layer structure as those used for the depth profiling. The experimental AFM surface roughness evolution was used to calculate the result of the depth profile measurements quantitatively. An excellent agreement was obtained between this calculation and the SNMS measurements. It was shown that the decrease in the intensity fluctuations during the depth profile analysis stems mainly from the increase in surface roughness of the samples studied, especially in the conventional sputtering mode. It was also concluded that the thickness fluctuation of the entire multilayer deposit and that of each layer are strongly correlated