National Repository of Grey Literature 10 records found  Search took 0.00 seconds. 
Structure and properties of DLC layers for industrial applications
Mates, Tomáš ; Ledinský, Martin ; Vetushka, Aliaksi ; Pikna, Peter ; Fejfar, Antonín ; Marek, A. ; Vyskočil, J. ; Erichsen, J. ; Dawah, P.
Diamond-like carbon (DLC) layers based on amorphous carbon are used for wide range of applications, mostly for mechanical protection of various industrial components. We examined DLC layers at micro- and nanoscale by two independent microscopic techniques: Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) with a good agreement. We compared DLC layers grown on steel substrate and Si wafer and found similarly structured clusters and a certain difference in the density of nucleation centres. The measurements of local mechanical properties by the AFM tip revealed that the Si wafer behaves as softer material compared to the growing DLC nanoclusters that also exhibit lower values in the map of the relative local friction coefficient. Finally, we observed changes in the Raman spectra of the DLC exposed to annealing at ambient conditions and found a gradual shift from the diamond phase to the graphite phase as a function of increasing temperature.
Summary report of results of the contract research between FZU AV ČR, v.v. i. and HVM Plasma s.r.o. for 2016
Mates, Tomáš ; Fejfar, Antonín ; Ledinský, Martin ; Vetushka, Aliaksi ; Pikna, Peter ; Bauerová, Pavla
Samples of protective layers based on DLC (Diamond-like-Carbon) on different substrates (test bodies and real components) were studied by several diagnostic methods.\nRaman spectroscopy was used for the detection of bindings in order to specify the structural variations, surface modifications both for as-deposited samples and particularly for samples that underwent different stress tests.\nScanning Electron Microscope (SEM) was used to examine the surface structure of layers in different locations on the sample and to search suitable test spots for the subsequent analysis by the Atomic Force Microscope (AFM). AFM in special modes was employed to measure the maps local mechanical properties (friction, tip adhesion, energy dissipation, etc.).\nOn a selected sample, the cross-sectional structure of the sample was analysed by the Focussed Ion Beam (FIB) and the elemental composition in various thicknesses was documented by the Energy-dispersive X-ray Spectroscopy (EDS).\n
Velké objekty v MOVPE strukturách s InAs/GaAs kvantovými tečkami
Samokhin, Jevgen ; Pangrác, Jiří ; Melichar, Karel ; Vavra, I. ; Jurek, Karel ; Mates, Tomáš ; Šimeček, Tomislav ; Hulicius, Eduard
The presence of large objects in MOVPE grown self-assembled quantum dot samples was studied. Creation of large objects and high indium concentration inside was explained as a combined process of accumulation of In atoms on the surface and their following long-range surface migration.
In situ monitorování růstu MOVPE InAs/GaAs struktur s kvantovými tečkami pomocí reflektanční anisotropické
Vyskočil, Jan ; Hospodková, Alice ; Pangrác, Jiří ; Melichar, Karel ; Oswald, Jiří ; Kuldová, Karla ; Mates, Tomáš ; Šimeček, Tomislav ; Hulicius, Eduard
Reflectance anisotropy spectroscopy (RAS) has been used for the real-time observation and optimization of single and double InAs/GaAs quantum dot layer structure growth. The properties of samples were ex situ characterized by photoluminescence and AFM.
Properties of InAs/GaAs quantum dots in vertically correlated structures with 2 QD layers grown by MOVPE
Vyskočil, Jan ; Hospodková, Alice ; Pangrác, Jiří ; Oswald, Jiří ; Mates, Tomáš ; Melichar, Karel ; Šimeček, Tomislav ; Hulicius, Eduard
We have studied the shape of QDs in structures with vertically correlated QDs where two layers of QDs were grown. We investigated the influence of spacer thickness on lateral shape (elongation) of QDs and photoluminescence intensity.
MOVPE InAs/GaAs quantum dots with long-wavelength emission
Oswald, Jiří ; Kuldová, Karla ; Hospodková, Alice ; Hulicius, Eduard ; Pangrác, Jiří ; Mates, Tomáš ; Melichar, Karel ; Vyskočil, Jan
One method which enables the shift of photoluminescence spectra of InAs/GaAs quantum dots toward longer wavelengths is the covering of the dots by In.sub.x./sub.Ga.sub.1-x./sub.As strain reducing layer. With the increasing x we have observed the shift of PL maxima from 1.28 μm to 1.46 μm.
Study of microcrystalline silicon by combined AFM microscope
Mates, Tomáš ; Fejfar, Antonín ; Rezek, Bohuslav ; Fojtík, Petr ; Drbohlav, Ivo ; Luterová, Kateřina ; Pelant, Ivan ; Kočka, Jan
Recent results by combined AFM (topography and local conductivity) and correlation between microstructure and electrical properties of thin silicon films.

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