Národní úložiště šedé literatury Nalezeno 18 záznamů.  předchozí11 - 18  přejít na záznam: Hledání trvalo 0.01 vteřin. 
Structuring of diamond films by reactive ion plasma etching
Domonkos, M. ; Ižák, Tibor ; Proška, J. ; Kromka, Alexander
In this study, two common strategies of diamond film structuring are described. Main focus is on the comparison of top-down and the bottom-up strategies. The top-down strategy is primary related to dry reactive ion etching through masking materials (or even without mask), while bottom-up strategy is based on selective area deposition of diamond film. Several methods of both strategies are demonstrated in details in the article, regarding to their properties and basic principles.
Foreign substrates pre-treatment using polymer composites in plasma-enhanced CVD growth of diamond fibers and layers
Potocký, Štěpán ; Babchenko, Oleg ; Ižák, Tibor ; Varga, Marián ; Kromka, Alexander ; Rezek, Bohuslav ; Tesárek, P.
Nanocrystalline diamond wires and layers were grown by microwave plasma CVD technique on Si substrates. The substrates were pretreated by non-woven composite nanofiber textile composed by poly(vinyl alcohol) matrix and ultra-dispersed diamond (UDD) nanoparticles prepared by needleless electrospinning method. High concentration of UDD in the PVA fibers lead to formation of diamond wires due to a combined effect of UDD particles used as seeding and high pressure difference across the fibers interface. A preferable growth of diamond layers was observed on areas with a low porosity volume of nanofiber textile. The influence of spundond structure on the growth of diamond decreased with lowering of UDD concentra-tion in the primary polymer matrix.
Review of nanocrystalline diamond film deposition on silicon and glass substrates down to 400 °C
Potocký, Štěpán ; Babchenko, Oleg ; Ižák, Tibor ; Varga, Marián ; Kromka, Alexander ; Rezek, Bohuslav ; Michalka, M.
We present an overview of a nanocrystalline diamond (NCD) films deposition on silicon and glass substrates by microwave plasma CVD in hydrogen-based gas mixture. The temperature plays a crucial parameter as the diamond growth process is temperature controlled. Use of temperature sensitive substrates demanded reducing substrate temperature. Natural decrease of deposition rate resulted in search of new or nonstandard process parameters which could at least minimize or compensate it. Addition of oxygen containing gasses was found to improve film quality, and increasing deposition speed. Moreover improvement in pre-treatment of foreign substrates allowed deposition of fully closed films in less then 100 nm. Low thickness of NCD always favorable due to lattice mismatch between substrate material and NCD film. Successful adoption of NCD film deposition on silicon and glass allowed us to study surface chemical modification for protein attachment and DNA immobilization.
H-terminated diamond-capped impedance transducer: Novel molecular sensor
Stehlík, Štěpán ; Ižák, Tibor ; Kromka, Alexander ; Dolenský, B. ; Havlík, M. ; Rezek, Bohuslav
Sensitivity of an intrinsic nano-crystalline diamond (NCD) layer to naphthalene Trogers base derivative decorated with pyrrole groups(TBPyr) was characterized by impedance spectroscopy. The transducer was made of Au interdigitated electrodes (IDE) with 50um spacing on alumina substrate which were capped with the NCD layer.
Influence of nucleation and methane concentration on buckypapers exposed to hot filament chemical vapor deposition process
Varga, Marián ; Kotlár, M. ; Vretenár, V. ; Ižák, Tibor ; Šoltýs, J. ; Kromka, Alexander ; Veselý, M.
In this article we investigate the nanocomposite material formation, particularly the deposition of nanocrystalline diamond film on buckypaper (BP) substrate. The buckypapers were prepared from single-wall carbon nanotubes (SWCNT) mixture produced by laser ablation method. We have investigated the influence of the nucleation and methane concentration on buckypapers exposed to the hot filament chemical vapor deposition process.
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.
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.

Národní úložiště šedé literatury : Nalezeno 18 záznamů.   předchozí11 - 18  přejít na záznam:
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