National Repository of Grey Literature 14 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Characterization of hydrogenated silicon thin films and diode structures with integrated germanium nanoparticles
Stuchlík, Jiří ; Fajgar, Radek ; Kupčík, Jaroslav ; Remeš, Zdeněk ; Stuchlíková, The-Ha
Substrates with ZnO (or ITO) conductive layers were covered by thin film of a-Si:H deposited by PECVD technique. Under a turbo-molecular vacuum (10-4 Pa) the reactive laser ablation (RLA) was used to cover this a-Si:H thin film by germanium NPs. The RLA was performed using focused excimer ArF laser beam (193 nm, 100 mJ/pulse) under SiH4 background atmosphere (0.5 Pa). As a target the elemental germanium was used. Reaction between ablated Ge and silane led to formation of Ge NPs covered by thin SiGe layer. Then the deposited NPs were covered and stabilized by a-Si:H layer by PECVD. Those two deposition processes was alternated and applied a few times. The Si:H thin films with integrated Ge NPs were characterized by microscopic, spectroscopic and diffraction techniques. I-V characteristics of final diode structures without and under illumination were measured as well as their electroluminescence behaviour.
The deposition of amorphous and amorphous hydrogenated silicon with embedded cubic Mg.sub.2./sub.Si nanoparticles
Stuchlíková, The-Ha ; Stuchlík, Jiří ; Remeš, Zdeněk ; Fajgar, Radek ; Galkin, N.G. ; Galkin, K.N. ; Chernev, I.M.
We study possibilities how to increase a by usage of magnesium silicide nanoparticles (Mg2Si-NPs) in structure of Si: H. In this paper we introduce two technics -combination of PECVD and Vacuum Evaporation (VE) and Reactive Laser Ablation (RLA) -for preparation of cubic structure of Mg2Si-NPs in amorphous (a-Si) or amorphous hydrogenated (a-Si: H) silicon matrix. Formation of Mg2Si-NPs was proved by Raman spectroscopy. Likewise we introduce optical changes measured at absorption edge and the first results on realized NIP structures.
Comparative study on functionalization of NCD films with amine groups
Artemenko, Anna ; Kozak, Halyna ; Stuchlík, Jiří ; Biederman, H. ; Kromka, Alexander
Two plasma-based processes for functionalization of oxygen or hydrogen terminated NCD surfaces with amino groups were compared. The first process was based on deposition of thin (8 nm) amine containing plasma polymer by RF magnetron sputtering of Nylon target in Ar/N-2 working gas mixture. RF plasma treatment in NH3 for 10 minutes was used in the second process. The properties of NCD films before and after amination were characterized by scanning electron microscopy (SEM), wettability measurements, spectral ellipsometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and current-voltage (I-V) measurements. The presence of nitrogen (and thus amino groups) on the surface was confirmed by XPS measurements in both cases. The obtained results indicated that NCD surface functionalization from amine containing plasma polymer by RF magnetron sputtering is an alternative technological solution for successful functionalization of diamond surfaces for biosensor applications.
The deposition of germanium nanoparticles on hydrogenated amorphous silicon
Stuchlík, Jiří ; Volodin, V.A. ; Shklyaev, A.A. ; Stuchlíková, The-Ha ; Ledinský, Martin ; Čermák, Jan ; Kupčík, Jaroslav ; Fajgar, Radek ; Mortet, Vincent ; More Chevalier, Joris ; Ashcheulov, Petr ; Purkrt, Adam ; Remeš, Zdeněk
We reveal the mechanism of Ge nanoparticles (NPs) formation on the surface of the hydrogenated amorphous silicon (a-Si:H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on ITO and a on boron doped nanocrystalline diamond (BDD). The coating of Ge NPs on a-Si:H was performed by molecular beam epitaxy (MBE) at temperatures up to 450 °C. The Ge NPs were characterized by Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The nanocrystalline Ge particles are conglomerates of nanocrystals of size 10-15 nm and quantum dots (QDs) with size below 2 nm embedded in amorphous Ge phase. After coating with Ge NPs the a-Si:H thin films show better adhesion on BDD substrates then on ITO substrates.
Hydrogen plasma treatment of ZnO thin films
Chang, Yu-Ying ; Neykova, Neda ; Stuchlík, Jiří ; Purkrt, Adam ; Remeš, Zdeněk
ZnO is an attractive wide band gap semiconductor with large exciton binding energy, high refractive index, high biocompatibility and diversety of nanostructure shapes which makes it suitable for many applications in the optoelectronic devices, optical sensors, and biosensors. We study the effect of hydrogen plasma treatment of the nominally undoped ZnO thin film deposited by DC reactive magnetron sputtering of Zn target in the gas mixture of argon and oxygen plasma. The SEM images show that the crystal size increases with film thickness. We confirm, that the electrical conductivity significantly increases after hydrogen plasma treatment by 4 orders of magnitude. Moreover, the increase of the infrared optical absorption, related to free carrier concentration, was detected below the optical absorption edge by the photothermal deflection spectroscopy.\n
The intrinsic submicron ZnO thin films prepared by reactive magnetron sputtering
Remeš, Zdeněk ; Stuchlík, Jiří ; Purkrt, Adam ; Chang, Yu-Ying ; Jirásek, Vít ; Štenclová, Pavla ; Prajzler, V. ; Nekvindová, P.
The DC reactive magnetron sputtering of metallic target in oxide atmosphere is a simple method of depositing the intrinsic (undoped) nanocrystalline layers of metal oxides. We have optimized the deposition of the intrinsic ZnO thin films with submicron thickness 50-500 nm on fused silica glass substrates and investigated the localized defect states below the optical absorption edge down to 0.01 % using photothermal deflection spectroscopy from UV to IR. We have shown that the defect density, the optical absorptance and the related optical attenuation in planar waveguides can be significantly reduced by annealing in air at 400 °C.
Nanopositioning with detection of a standing wave
Holá, M. ; Hrabina, J. ; Číp, O. ; Fejfar, Antonín ; Stuchlík, Jiří ; Kočka, Jan ; Oulehla, J. ; Lazar, J.
A measuring technique is intended for displacement and position sensing over a limited range with detection of standing-wave pattern inside of a passive Fabry-Perot cavity. In this concept we consider locking of the laser optical frequency and the length of the Fabry-Perot cavity in resonance. Fixing the length of the cavity to e.g. a highly stable mechanical reference allows stabilizing wavelength of the laser in air and thus to eliminate especially the faster fluctuations of refractive index of air due to air flow and inhomogeneity. Detection of the interference maxima and minima within the Fabry-Perot cavity along the beam axis has been tested and proven with a low loss transparent photodetector with very low reflectivity. The transparent photodetector is based on a thin polycrystalline silicon layer. Reduction of losses was achieved thanks to a design as an optimized set of interference layers acting as an antireflection coating. The principle is demonstrated on an experimental setup.
The optical spectra of carbon-based thin films measured by the photothermal deflection spectroscopy (PDS)
Remeš, Zdeněk ; Pham, T.T. ; Varga, Marián ; Kromka, Alexander ; Stuchlík, Jiří ; Mao, H.B.
Our photothermal deflection spectroscopy (PDS) setup allows to measure simultaneously the absolute values of the optical transmittance T, reflectance R and absorptance A spectra of thin layers on glass substrates in the spectral range from ultraviolet to near infrared light with the typical spectral resolution 5 nm in the ultraviolet, 10 nm in visible and 20 nm in the near infrared region. The PDS setup provides the dynamic detection range in the optical absorptance up to 4 orders of magnitude. Here we demonstrate the usability of this setup by comparing the optical absorbance on a series of the carbon layer and nanocrystalline diamond (NCD) thin layers deposited on glass substrates by using the magnetron sputtering and the microwave based surface wave discharge in linear antenna chemical vapor deposition (CVD) processes, respectively. The defect-induced localized states in the energy gap are observed in all carbon layers as well as in NCD.
Comparativ study on functionalization of NCD films with amine groups
Artemenko, Anna ; Kozak, Halyna ; Stuchlík, Jiří ; Biederman, H. ; Kromka, Alexander
Nanocrystalline diamond (NCD) films are considered as highly attractive material for biosensing due to its unique semiconducting properties. This can be achieved by modification of NCD films surface on molecular level. Typically chemical immobilization of biomoleculs requires the presence of active functional groups on the diamond surface. This was achieved by attachment of -NH2 functional groups on the surface of H- or O-terminated NCD surface via two plasma-based processes. The first process, deposition of thin amine containing polymer by RF magnetron sputtering of Nylon target in Ar/N2 gas mixture. The second process employs RF plasma treatment in NH3 for 10 minutes. Chemical derivatization (CD) XPS analysis revealed that polymeric coating exhibits a higher amount of amino groups than the diamond surface treated in NH3 RF plasma. Results of I-V measurements showed that surface conductivity of H-terminated NCD films was preserved only after the RF sputtering.
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.

National Repository of Grey Literature : 14 records found   1 - 10next  jump to record:
See also: similar author names
2 Stuchlík, J.
2 Stuchlík, Jakub
6 Stuchlík, Jan
2 Stuchlík, Jaroslav
1 Stuchlík, Josef
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