Národní úložiště šedé literatury Nalezeno 19 záznamů.  1 - 10další  přejít na záznam: Hledání trvalo 0.00 vteřin. 
In situ XPS characterization of diamond films after AR.sup.+./sup. cluster ion beam sputtering
Artemenko, Anna ; Babchenko, Oleg ; Kozak, Halyna ; Ukraintsev, Egor ; Ižák, Tibor ; Romanyuk, Olexandr ; Potocký, Štěpán ; Kromka, Alexander
In this work, in situ XPS analysis of chemical composition of H- and O-terminated nano- and microcrystalline diamond (NCD and MCD) films before and after their sputtering by the Ar+ cluster ion beam was investigated. Scanning electron microscopy confirmed sputtering of all diamond surfaces with a rate about 0.5 nm/min. Raman spectroscopy and XPS revealed surface graphitization of diamond surface induced by sputtering. Moreover, XPS data showed the presence of about 0.7 % of Ar atoms on the investigated diamond surface after 66 min of sputtering. Also, oxygen residuals were still presented on the H-NCD surface after 66 min of sputtering. In contrast, no oxygen was found on the H-MCD surface just after 2 min of sputtering. Surface composition is discussed in respect to the diamond films growth parameters and surface structure.
Hydrogen-terminated diamond surface as gas sensing layer working at room temperature
Davydova, Marina ; Kulha, P. ; Babchenko, Oleg ; Kromka, Alexander
Effect of fluorine- and hydrogen-terminated diamond surface on the gas sensing properties at room temperature was investigated. The gas sensing properties diamond-based sensor were measured by the changes of electrical resistance to various volatile organic compounds (C6H6, C3H6O, isopropylalcohol) and relative humidity. The comparative sensing performance of hydrogenated diamond surface shows improvement in sensitivity toward benzene, acetone, isopropylalcohol and humid air in contrast to fluorinated diamond surface, where the surface conductivity was suppressed.
Effect of H- and O-termination of nanocrystalline diamond films on cell adhesion and osteogenic differentiation
Lišková, Jana ; Babchenko, Oleg ; Varga, Marián ; Kromka, Alexander ; Hadraba, Daniel ; Švindrych, Zdeněk ; Bačáková, Lucie
In order to control the hydrophobic or hydrophilic character, the NCD film surfaces were grafted by hydrogen atoms (H-termination) or by oxygen atoms (O-termination). Human mesenchymal stem cells and primary human osteoblasts were used for biological studies on H- and O-terminated NCD films. We found that cells cultivated on O-terminated NCD films exhibit better adhesion than H-terminated NCD films. In addition, the expression of osteogenic cell markers collagen and alkaline phosphatase analysed by Realtime PCR and immunostaining was higher on O-terminated films.
Fabrication of 3D diamond membranes for microfluidic systems
Varga, Marián ; Babchenko, Oleg ; Bauerová, Pavla ; Hruška, Karel ; Jurka, Vlastimil ; Kromka, Alexander ; Rezek, Bohuslav
Perfusion of cell medium, especially in microfluidic devices, can provide in-vivo-like conditions for cell cultures. The most recent demand on such systems is to include electronically active artificial cell support for in-situ monitoring. Diamond thin films exhibit advantageous combination of physical, mechanical, chemical, biocompatible and electronic properties for this purpose. In this work we explore two strategies for fabrication of self-standing three-dimensional nanocrystalline diamond membrane for implementation in microfluidic invivo like experiments: i) nucleation and chemical vapour deposition (CVD) growth of diamond on porous 3D carbon foam (with 80 pores per inch) and ii) selective diamond growth predefined by photolithographic processing using copper grid mask. The morphology and material quality of the fabricated membranes are characterized by scanning electron microscopy and Raman spectroscopy.
Study of nucleation and growth of diamond thin films
Ižák, Tibor ; Babchenko, Oleg ; Varga, Marián ; Potocký, Štěpán ; Marton, M. ; Vojs, M. ; Domonkos, Mária ; Kromka, Alexander
This study deals with the nucleation and growth of CVD diamond films on Si substrates. In nucleation part two different nucleation methods were studied: (i) the bias enhanced nucleation (BEN) and (ii) ultrasonic seeding. In the case of BEN, (i) the nucleation time and (ii) the influence of bias voltage were studied. For ultrasonic seeding the effect of different solutions of ultradisperzed detonation nanodiamond (UDD) powder with metal particles on the nucleation efficiency and growth process was investigated (i.e. diamond powder, nanosized Ni, microsized Co and Y metal powders).
Intrinsic and boron-doped diamond microstructured for electrochemical batteries
Kromka, Alexander ; Babchenko, Oleg ; Rezek, Bohuslav ; Ižák, Tibor ; Libertínová, Jitka ; Hruška, Karel ; Nyholm, L. ; de Oliviera Jorge, E.
Diamond - widest electrochemical window, excellentfor covalent binding of molecules, effective csarge transfer.
High resolution ATR FTIR spectroscopy of hydrogenated diamond nanoparticles using NCD-coated prism
Remeš, Zdeněk ; Kozak, Halyna ; Rezek, Bohuslav ; Babchenko, Oleg ; Kromka, Alexander ; Girard, H. ; Petit, T. ; Arnault, J. ; Bergonzo, P.
Crucial part of successful ATR - linear antenna CVD NCD. ATR IR spectroscopy compared to transmittance FTIR spectroscopy. IR spectra of diamant nanoparticles adsorbed on NCD surface. Advances of ATR FTIR - higher sensitivity, better resolution, reproducibility.
Gas sensing properties of IDT devices employing H-terminated NCD films and their nano-structures
Kromka, Alexander ; Davydova, Marina ; Babchenko, Oleg ; Rezek, Bohuslav ; Stuchlík, Jiří
Embedded metal electrode in IDTs (novel concept). Surface conductivity, H-termination of is crucial. Surface conductivity sensitive to testing gas (oxidizing/reducing). Largest surface conductivity for fosgene. Temperature experiments, optimal temperature.
Optically and electronically active diamond-silicon photonic structures: state and outlooks
Ondič, Lukáš ; Dohnalová, Kateřina ; Kůsová, Kateřina ; Cibulka, Ondřej ; Ledinský, Martin ; Babchenko, Oleg ; Kromka, Alexander ; Rezek, Bohuslav ; Pelant, Ivan
We have prepared the photonic crystal at the top of the nanocrystalline diamond layer. We have obtained the effective extraction of diamond intrinsic photoluminescence via leaky modes. We have shown the simulation of optical gain enhancement in the photonic crystal.

Národní úložiště šedé literatury : Nalezeno 19 záznamů.   1 - 10další  přejít na záznam:
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