National Repository of Grey Literature 16 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, J. ; Fajgar, R. ; Remeš, Z. ; Kupčík, Jaroslav ; Stuchlíková, H.
P-I-N diode structures based on the thin films of amorphous hydrogenated silicon (a-Si: H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique were prepared with embedded Si and Ge nanoparticles. The Reactive Laser Ablation (RLA) of germanium target was used to cover the intrinsic a-Si: H layer by Ge NPs under a low pressure of the silane. The RLA was performed using focused excimer ArF laser beam under SiH4 background atmosphere. Reaction between ablated Ge NPs and SiH4 led to formation of Ge NPs covered by thin GeSi: H layer. The deposited NPs were covered and stabilized by a-Si: H layer by PECVD. Those two deposition processes were alternated repeatedly. Volt-ampere characteristics of final diode structures were measured in dark and under illumination as well as their electroluminescence spectra.
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.
MOCVD Iron Oxide Nanoparticle Generation not Only for Follow-Up Inalation Exposure Experiments.
Moravec, Pavel ; Schwarz, Jaroslav ; Vodička, Petr ; Kupčík, Jaroslav ; Švehla, Jaroslav
Iron oxide nanoparticles (NPs) are industrially produced and commercially available and they are also frequently emitted into the environment by iron making plants. In the human body, iron is maintained at homeostatic fairly low level. However, freshly generated iron oxide NPs cause febrile and inflammatory response known as metal fume fever, but the potential in vivo consequences of inhalation of iron oxide NPs from the atmosphere has not yet been investigated. An overview of recent studies evaluating iron oxide NPs cytotoxicity, genotoxicity, developmental toxicity and neurotoxicity was presented by Valdiglesias et al. (2015). Toxicity of iron oxide NPs has been studied both in vitro and in vivo. Exposure chamber for the whole body inhalation experiments with small laboratory animals was constructed at the Institute of Analytical Chemistry of the CAS (Večeřa et al., 2011) and some methods of NPs generation for these experiments were already tested in our laboratory (Moravec et al., 2015. Moravec et al., 2016). In this study we tested a method of long lasting generation of iron oxide NPs by pyrolysis and oxidation of ironIII acetylacetonate (FeAA3).
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The deposition of germanium nanoparticles on hydrogenated amorphous silicon.
Stuchlík, J. ; Volodin, V.A. ; Shklyaev, A.A. ; Stuchlikova, T.H. ; Ledinsky, M. ; Čermák, J. ; Kupčík, Jaroslav ; Fajgar, R. ; Mortet, V. ; More-Chevalier, J. ; Ashcheulov, P. ; Purkrt, A. ; Remeš, Z.
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 degrees 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.
Nanoparticle Generation for Follow-Up Exposure Studies by Oxidation of Copper Acetylacetonate.
Moravec, Pavel ; Schwarz, Jaroslav ; Vodička, Petr ; Švehla, Jaroslav ; Kupčík, Jaroslav
The exposure to nanoparticles (NPs) represents a severe problem to human health, because they are becoming more widely used and their number of applications continually increases. Particles containing copper are emitted from smelters, iron foundries, power stations and municipal incinerators (WHO, 1998), as well as from brake linings during braking, Kukutschova et al. (2011). Copper and copper oxide NPs are frequently used as catalysts, heat transfer fluids in machine tools (Kim et al., 2011), inks, anode material in lithium-ion batteries (Guo et al., 2002) and many others. Even though CuO NPs were found highly toxic, Karlsson et al. (2008) and it is likely that NPs enter human body via respiratory tract, the inhalation exposure experiments of CuO NPs with laboratory animals are still rather rare (Pettibone et al., 2008 and Lebedova et al., 2016). The exposure chamber for long lasting inhalation experiments was constructed at the Institute of Analytical Chemistry of the CAS (Večeřa et al., 2011) and some methods of NPs generation for these experiments were already tested in our laboratory (Moravec et al., 2015 and Moravec et al., 2016a). The generation of Cu/Cu2O NPs by thermal decomposition of copper acetylacetonate (CuAA) was reported by Moravec et al. (2016b) and here we present the results of long lasting generation of NPs by oxidation of CuAA.
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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.
Generation of NPS for Exposure Experiments from Copper Acetylacetone.
Moravec, P. ; Schwarz, J. ; Vodička, P. ; Kupčík, Jaroslav ; Švehla, J.
Particles containing copper are emitted from smelters, iron foundries, power stations, and municipal incinerators (WHO, 1998) and also from brake linings during breaking, Kukutschová et al. (2011). Nanoparticles (NPs) of copper are ingredients in polymers, inks, and bioactive coatings inhibiting the growth of microorganisms, Cioffi at al. (2005), and CuO NPs has been used in antimicrobial textiles, Gabbay and Borkow (2006), therefore they can be easily inhaled. Even though CuO NPs were found highly toxic, Karlsson et al. (2008), in vivo studies of their toxicity are still rather rare. In this work we tested a method of long lasting nanoparticle generation from copper acetylacetonate (CuAA) for use in follow up exposure experiments with laboratory animals. The exposure chamber for inhalation experiments was constructed in the Institute of Analytical Chemistry AS CR (Večeřa et al., 2011) and some methods of NPs generation for these experiments were already tested in our laboratory (Moravec et al., 2015, Moravec et al., 2016).
Generation of NPS for Exposure Experiments from Copper Acetylacetone.
Moravec, Pavel ; Schwarz, Jaroslav ; Vodička, Petr ; Kupčík, Jaroslav ; Švehla, Jaroslav
Particles containing copper are emitted from smelters, iron foundries, power stations, and municipal incinerators (WHO, 1998) and also from brake linings during breaking, Kukutschová et al. (2011). Nanoparticles (NPs) of copper are ingredients in polymers, inks, and bioactive coatings inhibiting the growth of microorganisms, Cioffi at al. (2005), and CuO NPs has been used in antimicrobial textiles, Gabbay and Borkow (2006), therefore they can be easily inhaled. Even though CuO NPs were found highly toxic, Karlsson et al. (2008), in vivo studies of their toxicity are still rather rare. In this work we tested a method of long lasting nanoparticle generation from copper\nacetylacetonate (CuAA) for use in follow up exposure experiments with laboratory animals. The exposure chamber for inhalation experiments was constructed in the\nInstitute of Analytical Chemistry AS CR (Večeřa et al., 2011) and some methods of NPs generation for these experiments were already tested in our laboratory (Moravec et al., 2015, Moravec et al., 2016).
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