1.

Silicon surface deoxidation using strontium oxide deposited with the pulsed laser deposition technique

The applicability of the chemically much more stable SrO compared to metallic Sr in the process of native-oxide removal and silicon-surface stabilization was investigated using the pulsed-laser deposition technique (PLD), while the as-derived surfaces were analyzed in-situ using reflection high-energy electron diffraction and ex-situ using X-ray photoelectron spectroscopy, X-ray reflectivity, and atomic force microscopy. After the deposition of the SrO over Si/SiO2, in a vacuum, different annealing conditions, with the temperature ranging up to 850 °C, were applied. The results of the study revealed, for the first time, an effective pathway for the preparation of a SrO-induced buffer layer on a silicon substrate using PLD, which can be subsequently utilized for the epitaxial growth of functional oxides.

COBISS.SI-ID: 28025383

2.

Hydroxyapatite/gold/arginine: Designing the structure to create antibacterial activity

We designed hydroxyapatite/gold/arginine (HAp/Au/arginine) nanocomposite that contains: (i) hydrophobic gold (Au) nanoparticles, (b) positively charged, hydrophilic arginine molecules that functionalize the surface of the Au and (c) hydroxyapatite (HAp) bioactive carrier of the functionalized Au nanoparticles. None of the components used for the formation of the nanocomposite have any influence on bacterial growth; however, their combination within the nanocomposite that creates specific and surface provides this property. In comparison to the non-selective HAp/Ag reference, newly-developed material possesses stronger antibacterial action, is more compatible to human cells. Concerning the properties of new material it can be suggested as safer and more effective replacement of silver-based antibacterial components in biomaterials.

COBISS.SI-ID: 27352359

3.

Chemical decomposition as a likely source of ambient and thermal instabilities of layered sodium cobaltate

This article deals with synthesis of highly textured sodium cobaltate Na0.75CoO2 and changes of their properties at different ambient conditions. At the same time, we identified its peculiarities that influence the measured parameters to a degree that poses serious questions about this material’s potential for use. We have systematically studied the influence of humidity on the ceramic pellets and identified the conditions under which the material completely deteriorates. By performing microstructural and thermal analyses, coupled with a determination of the evolved gases, we identified the chemical reactions that are involved in this process. The changes in the physical parameters can be attributed to the reduction of cobalt and consequently to the formation of CoO inclusions, which increases the amount of sodium in the sodium cobaltate lattice.

COBISS.SI-ID: 27467815

4.

Pulsed laser deposition of SrTiO[sub]3 on a H-terminated Si substrate

In our study, pulsed laser deposition was used to prepare a SrTiO3 (STO) thin film on a H-terminated Si substrate. The main purpose of our work was to verify the ability of H-termination against the oxidation of Si during the PLD process and to analyze the resulting interfaces. In the first part of the study, the STO was deposited directly on the Si, leading to the formation of a preferentially textured STO film with a (100) orientation. In the second part, SrO was used as a buffer layer, which enabled the partial epitaxial growth of STO with STO (110)//Si(100) and STO[001]//Si[001]. The change in the growth direction induced by the application of a SrO buffer was governed by the formation of a SrO(111) intermediate layer and subsequently by the minimization of the lattice misfit between the STO and the SrO. Under the investigated conditions, approximately 10 nm thick interfacial layers formed due to reactions between the deposited material and the underlying Si. In the case of direct STO deposition, SiOx formed at the interface with the silicon, while in the case when SrO was used as a buffer, strontium silicate grew directly on the silicon, which improves the growth quality of the uppermost STO.

COBISS.SI-ID: 26882855

5.

Weak polyion multilayer-assisted in situ synthesis as a route toward a plasmonic Ag/TiO[sub]2 photocatalyst

Polyelectrolyte multylayers were assembled on silicon substrate and used for in-situ synthesis of silver nanoparticles. Subsequently Ti-isopropoxide was applied which triggered in-situ sol gel reaction. After thermal decomposition of organic phases Ag/TiO2 nanocomposite was obtained. The composite exhibited superior photocatalytic activity to that of titania. The effect was attributed to surface plasmon assisted charge separation.

COBISS.SI-ID: 23788071