National Repository of Grey Literature 61 records found  beginprevious52 - 61  jump to record: Search took 0.00 seconds. 
Influence of methane concentration on diamond film morphology and growth rate
Ižák, Tibor ; Babchenko, Oleg ; Kromka, Alexander ; Potměšil, Jiří ; Hruška, Karel
In this study we investigated the influence of methane concentration on the diamond film growth. The experiments were carried out in focused microwave chemical vapour deposition system. The methane concentration was varied from 0.5% to 10 % of CH4 in H2 atmosphere. The final film morphology, chemical composition and growth rate were investigated by scanning electron microscopy (SEM), Raman spectroscopy and optical reflectance measurement. We observed, that increasing of CH4 concentration enhances the growth rate, but at the expense of the diamond film quality.
Influence of CO.sub.2./sub. concentration on diamond film morphology in pulsed linear antenna microwave plasma CVD system
Domonkos, M. ; Ižák, Tibor ; Babchenko, Oleg ; Kromka, Alexander ; Hruška, Karel
The diamond films were deposited in a pulsed linear antenna microwave plasma system. The influence of CO2 addition into the standard CH4/H2 gas mixture on the diamond film morphology was investigated. The concentration of CO2 varied from 0% up to 80% in CO2/CH4/H2 gas mixture. The film morphology, the growth rate and the ratio of sp3/sp2 carbon bonds were investigated. It was found that increasing of CO2 concentration resulted in enhanced growth rate (from 20 up to 36 nm/h). However, at very high CO2 concentrations (>40%) dominates etching instead of growth process. Moreover, we found that increasing of CO2 enhances the diamond film quality.
Deposition of carbon nanotubes by MW PECVD method
Babchenko, Oleg ; Davydova, Marina ; Hruška, Karel ; Kromka, Alexander
The report is about the growth of carbon nanotubes from CH4/H2 gas mixture applying linear antenna plasma system. We investigate growth of nanotubes in the different type of plasma and by using different catalyst particles.
Electrostatic assembly of alumina nanoparticles on nanocrystalline diamond films
Verveniotis, Elisseos ; Kromka, Alexander ; Rezek, Bohuslav
We apply atomic force microscope for local electrostatic charging of oxygen-terminated nanocrystalline diamond (NCD) thin films deposited on silicon, to induce electrostatically driven self-assembly of colloidal alumina nanoparticles into micro-patterns. The NCD films have sub-100 nm thickness and 60% relative sp2 phase content. We characterize charge contrast and stability in air, fluorocarbon oil and water by Kelvin force microscopy. We discuss factors influencing the charging process and demonstrate that the contrast of more than ± 1 V is needed to induce selfassembly of the nanoparticles via coulombic and polarization forces.
Characteristics of nanocrystalline diamond SGFETs under cell culture conditions
Krátká, Marie ; Kromka, Alexander ; Rezek, Bohuslav ; Brož, A. ; Kalbáčová, M.
Characterization of electronic properties of protein diamond interface by using microscopic (20 μm) solution-gated field-effect transistors (SGFET) based on H-terminated nanocrystalline diamond films (NCD) on glass. We show that NCD films with grain sizes down to 80 nm and thickness down to 100 nm are operational as SGFETs.
Pulsed linear antenna microwave plasma – a step ahead in large area material depositions and surface functionalization
Kromka, Alexander ; Babchenko, Oleg ; Ižák, Tibor ; Potocký, Štěpán ; Davydova, Marina ; Neykova, Neda ; Kozak, Halyna ; Remeš, Zdeněk ; Hruška, Karel ; Rezek, Bohuslav
A technological progress in the large area growth of diamond films and carbon nanotubes by the modified linear antenna MW system is presented. We show a correlation between process parameters and nano- or poly-crystalline film character. A challenging part, diamond coated mirrors or ATR prisms, are shown as multifunctional optical elements suitable for detection of absorbed molecules. Additional positive feature of the presented plasma system is low temperature hydrogen functionalization of diamond films. Finally, we present that combination of pulsed MW plasma with radiofrequency substrate biasing results in growth of oriented CNTs over large area.
Linear antenna microwave plasma treatment of diamond
Neykova, Neda ; Kozak, Halyna ; Kromka, Alexander ; Bryknar, Z. ; Vaněček, Milan
The presented works reports on a hydrogen termination of nano-crystalline diamond films performed at low temperature.
Plošný přenos náboje na rozhraní polypyrol-diamant
Čermák, Jan ; Rezek, Bohuslav ; Hubík, Pavel ; Mareš, Jiří J. ; Kromka, Alexander ; Fejfar, Antonín
In this study we examine in-plane hole transport in polypyrrole-diamond interface.
Lokální elektrostatické nabíjení polovodičových tenkých vrstev
Verveniotis, Elisseos ; Čermák, Jan ; Kromka, Alexander ; Rezek, Bohuslav
In this study we examine local electrostatic charging of semiconductor thin films.
Charge transport at polypyrrole diamond interface
Rezek, Bohuslav ; Čermák, Jan ; Kromka, Alexander ; Ledinský, Martin ; Kočka, Jan
Changes of surface potential and photo-current under illumination indicate exciton splitting at the polypyrrole-diamond interface and transport of holes to diamond.

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