2D kovový wolfram

2D metallic material is an important group member in 2D material family. Many applications have been applied in the catalysis and devices. In this paper, we present a novel method to prepare the tungsten 2D material, which is simple and powerful. The W thin film is deposited via magnetron sputtering. As-deposited tungsten thin film is able to be exfoliated with wet and dry methods. We show a clear layered structure of the tungsten thin film from the cross sectional view. Via the exfoliation, an large area 2D tungsten monolayer is obtained. After oxidation, the 2D material shows potentials in electric signal transport.2D kovový materiál je důležitým členem skupiny ve skupině 2D materiálů. Mnoho aplikací bylo použito v katalýze a v dalších zařízeních. V tomto příspěvku představujeme novou metodu přípravy wolframového 2D materiálu, která je jednoduchá a výkonná. Tenký film W je nanášen magnetronovým rozprašováním. Takto nanesený tenký film wolframu lze odlupovat mokrými a suchými metodami. V řezu vrstvou presentujeme jasnou vrstvenou strukturu wolframového tenkého filmu. Prostřednictvím exfoliace se získá velkoplošná 2D monovrstva wolframu. Po oxidaci ukazuje je 2D materiál slibný v přenosu elektrického signálu

Vrstevnatý materiál s fázovou změnou na bázi Ge2Sb2Te5

In this study, a universal Ge2Sb2Te5 phase change material was sputtered to obtain a layered structure. The crystalline phase of this material was prepared by annealing. SEM (scanning electron microscopy) and HRTEM (high-resolution transmission electron microscopy) images give confirmed that the sputtered Ge2Sb2Te5 thin film in crystalline phase has multiple layers. The layers can be exfoliated by acetone. The thicknesses of acetone-exfoliated crystalline and amorphous flakes are approx. 10–60 nm.V této studii byl připraven univerzální materiál Ge2Sb2Te5 s fázový přechodem a vrstevnatou strukturou pomocí metody naprašování.Krystalická fáze materiálu byla připravena pomocí temperace. SEM (skenovací elektronová mikroskopie) a HRTEM (transmisní elektronová mikroskopie s vysokým rozlišením) scany potvrdily, že naprášené vrstvy Ge2Sb2Te5 v krystalické fázi byly tvořeny mnoha vrstvami. Nalezené vrstvy byly úspěšně exfoliovány v acetonu. Tloušťka krystalických a amorfních v acetonu exfoliovaných vrstev byla cca. 10-60nm

Electroluminescence of thin film

Hydrogenated amorphous substoichiometric silicon carbon alloys (a-SiC:H) with and without embedded Ge nanoparticles (NPs) have been prepared by plasma enhanced chemical vapour deposition combined with in-situ Ge evaporation and annealing on semi-transparent boron doped nano-crystalline diamond coated Ti grids. The presence of Ge NPs embedded in the amorphous phase has been confirmed by transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses. Current-voltage (I–V) characteristics and near infrared electroluminescence (EL) spectra were measured to compare performance of diodes. The relatively strong EL appears in diodes with integrated Ge NPs near the direct band-gap transition of Ge at about 0.82 eV with an intensity strongly correlating with current density. However, it has also been found that Ge NPs integrated into a-SiC:H significantly deteriorates diode I–V characteristic

Multimodální kontrastní látky umožňující snímání pH na podkladě organickými molekulami funkcionalizovaných zlatých nanoslupek s manganato-zinečnato feritovým jádrem

Highly complex nanoparticles combining multimodal imaging with the sensing of physical properties in biological systems can considerably enhance biomedical research, but reports demonstrating the performance of a single nanosized probe in several imaging modalities and its sensing potential at the same time are rather scarce. Gold nanoshells with magnetic cores and complex organic functionalization may offer an efficient multimodal platform for magnetic resonance imaging (MRI), photoacoustic imaging (PAI), and fluorescence techniques combined with pH sensing by means of surface-enhanced Raman spectroscopy (SERS). In the present study, the synthesis of gold nanoshells with Mn-Zn ferrite cores is described, and their structure, composition, and fundamental properties are analyzed by powder X-ray diffraction, X-ray fluorescence spectroscopy, transmission electron microscopy, magnetic measurements, and UV-Vis spectroscopy. The gold surface is functionalized with four different model molecules, namely thioglycerol, meso-2,3-dimercaptosuccinate, 11-mercaptoundecanoate, and (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide, to analyze the effect of varying charge and surface chemistry on cells in vitro. After characterization by dynamic and electrophoretic light scattering measurements, it is found that the particles do not exhibit significant cytotoxic effects, irrespective of the surface functionalization. Finally, the gold nanoshells are functionalized with a combination of 4-mercaptobenzoic acid and 7-mercapto-4-methylcoumarin, which introduces a SERS active pH sensor and a covalently attached fluorescent tag at the same time. H-1 NMR relaxometry, fluorescence spectroscopy, and PAI demonstrate the multimodal potential of the suggested probe, including extraordinarily high transverse relaxivity, while the SERS study evidences a pH-dependent spectral response.Vysoce komplexní nanočástice kombinující multimodální zobrazování se snímáním fyzikálních vlastností v biologických systémech mohou výrazně zlepšit biomedicínský výzkum. Zlaté nanoslupky s magnetickými jádry a komplexní organickou funkcionalizací mohou nabídnout účinnou multimodální platformu pro zobrazování magnetickou rezonancí (MRI), fotoakustické zobrazování (PAI) a fluorescenční techniky kombinované se snímáním pH pomocí povrchově zesílené Ramanovy spektroskopie (SERS). V této studii je popsána syntéza zlatých nanoslupek s Mn-Zn feritovými jádry, a také jejich struktura, složení a základní vlastnosti. Zlatý povrch byl funkcionalizován čtyřmi různými modelovými molekulami, jmenovitě thioglycerolem, meso-2,3-dimerkaptosukcinátem, 11-merkaptoundekanoátem a (11-merkaptoundecyl)-N,N,N-trimethylamoniumbromidem. Bylo zjištěno, že částice nevykazují významné cytotoxické účinky, bez ohledu na funkcionalizaci povrchu. Nakonec byly zlaté nanoslupky funkcionalizovány kombinací kyseliny 4-merkaptobenzoové a 7-merkapto-4-methylkumarinu. NMR relaxometrie, fluorescenční spektroskopie a PAI demonstrují multimodální potenciál navrhované sondy, včetně mimořádně vysoké příčné relaxivity, zatímco studie SERS potvrzuje spektrální odezvu závislou na pH

Radiation-induced phase separation in nanostructured Hf-In-C ternary thin films under irradiation with 200 keV Ar+ ion beam

Thin films consisting of 17 groups of Hf/In/C multilayers cyclically alternating layers of Hf, In and C each with a thickness of 4-5 nm were synthesized by ion sputtering using a 25 keV Ar+ ion beam with 400 mu A current and targets made of pure hafnium, indium and carbon. The films were subsequently annealed in vacuum at 120 degrees C for 24 hours to induce intermixing of elements phases, their interaction, and formation of the Hf-In-C nanostructures (including the Hf2InC MAX phase). After fabrication, a part of the pristine (as deposited) samples was irradiated by 200 keV Ar+ ions at high fluences 10(15) and 10(17) cm(-2). Both samples (as prepared and irradiated) were analyzed by IBA nuclear analytical methods, as well as by AFM and TEM microscopic techniques, and by XPS and profilometry to understand the microstructural evolution. Moreover, nanoindentation analysis was performed to assess the effects of ion irradiation on the microstructure and mechanical properties of the films. The experimental results showed that thin Hf-In-C nanostructured films can be formed by ion sputtering with promising mechanical parameters. The irradiated Hf-In-C films were found to be resistant only up to a fluence of about 10(15) Ar cm(-2). At higher fluences it degrades, and Hf2InC transforms to the binary HfC0.95 phase due to sublimation of In. At 10(17) cm(-2) the original matrix (including M(2)AX) is destroyed, and instead, a mixture of MX binary phases (e.g. HfC0.95) and crystalline oxides (e.g. HfO2 and In2O3) are formed