Search results for "substrate"
showing 10 items of 1018 documents
Photoconductivity and optical properties of silicon coated by thin TiO2 film in situ doped by Au nanoparticles
2013
Light trapping enhancement by plasmonic-active metal nanoparticles (NPs) is believed to be a promising approach to increase silicon-based solar cell efficiency. Therefore, we investigated TiO2 films in situ doped by Au NPs (TiO2:AuNPs) deposited by spin coating on a silicon substrate. Photoconductivity and optical properties of the TiO2:AuNPs/Si structures were studied in comparison with those of TiO2/Si reference samples. We found that an introduction of the 40–50 nm diameter AuNPs into the antireflective TiO2 layer deteriorates the antireflection properties and decreases the external yield of photogeneration of charge carriers. This is due to an increase of the layer reflection in the red…
Initial stages of TiO2 thin films MOCVD growth studied by in situ surface analyses
2005
Abstract In situ chemical surface analyses using X-ray photoelectron spectroscopy (XPS) were performed to understand the initial stages of TiO 2 thin-film MOCVD growth. Deposits on Si (1 0 0), a few nanometres thick, were obtained at a fixed temperature of 650 °C and for two different pressures, 2.9 and 0.05 mbar, using titanium tetraisopropoxide (TTIP) as precursor. Pressure lowering led to a higher deposit growth rate. Reduction of titanium with respect to stoichiometric titanium dioxide and oxidation of the wet-cleaned silicon substrate are observed from decomposition of the Ti 2p and Si 2p peaks. The formation of a TiSi x O y mixed oxide is also pointed out and confirmed by the presence…
Structural, electrical and optical characteristics of Al-doped zinc oxide thin films deposited by reactive magnetron sputtering
2013
ZnO:Al (AZO) thin films on glass were deposited by DC reactive magnetron sputtering at approximately 300°C substrate temperature. Structural, electrical and optical properties were investigated as a function of oxygen flow. XRD data shows that AZO thin films are polycrystalline with pronounced c-axis orientation and the grain size increasing with the oxygen flow. The lowest achieved resistivity within the deposited set of samples was 7.6·10 -4 Ωcm. The transmittance of AZO films was above 80 % at 550 nm with the optical band gap between 3.4 and 3.8 eV.
Screening and mapping of pigments in paintings using scanning electrochemical microscopy (SECM)
2015
The use of the scanning electrochemical microscopy (SECM) technique for identifying and mapping of both organic and inorganic pigments in sub-microsamples from pictorial specimens is described. This methodology, inspired by the voltammetry of immobilized particles technique, permits the study of textural properties of paint layers and mapping the distribution of pigment grains upon application of different potentials to the substrate. A combination of the redox competition SECM strategy with voltammetry yields a local identification methodology for different organic and inorganic pigments in paint samples.
Photoinduced direct surface relief formation in amorphous As40S15Se45 films
2013
Abstract The surface relief grating formation in As40S15Se45 films under He–Ne laser wave-length λ = 0.6328 μm light influence was examined. The obtained experimental results showed the strong dependence of photoinduced surface relief depth on illumination dose and film thickness during holographic recording from film side as well as from glass substrate side. The surface relief grating profile over the thickness range 0.13
Angle resolved X-ray photoemission spectroscopy double layer model for in situ characterization of metal organic chemical vapour deposition nanometri…
2007
International audience; In situ Angle Resolved X-ray Photoemission Spectroscopy (ARXPS) characterizations of TiO2 thin films grown on silicon by Metal Organic Chemical Vapour Deposition were performed in order to get information on interfacial reactions at the first stages of the growth, one of the aims being to understand the influence of deposition conditions. Thickness measurements were also carried out from ARXPS analyses. As the real structure of the films was shown to be a double layer system such as TiO2/SiO2/Si, an ARXPS model of thickness and surface coverage determination was applied to each layer independently. However, the application of this model to very thin films underestima…
Surfactant effect of Sb on the growth of Ag films on a sapphire substrate
1996
It is shown that a very thin layer of Sb may be used as a surfactant to modify the growth of silver films on an insulating substrate. The conduction (percolation) current flowing through a dispersed Ag film appears at a significantly smaller thickness due to the change in the growth mode of silver islands. Some practical applications are indicated.
Some aspects of formation and tribological properties of silver nanodumbbells.
2013
In this paper, metal nanodumbbells (NDs) formed by laser-induced melting of Ag nanowires (NWs) on an oxidized silicon substrate and their tribological properties are investigated. The mechanism of ND formation is proposed and illustrated with finite element method simulations. Tribological measurements consist in controllable real-time manipulation of NDs inside a scanning electron microscope (SEM) with simultaneous force registration. The geometry of NDs enables to distinguish between different types of motion, i.e. rolling, sliding and rotation. Real contact areas are calculated from the traces left after the displacement of NDs and compared to the contact areas predicted by the contact m…
Laser Ultrasonic Testing for Estimation of Adhesion of Al2O3Plasma Sprayed Coatings
2001
Abstract The aim of the present study was to investigate the possibility of using a laser ultrasonic technique for the estimation of the adhesion of ceramic coatings, deposited onto metallic substrates by thermal spraying techniques. For this purpose, a pulsed Nd : YAG laser (λ = 1064 nm, 14 ns) was used to irradiate Al2O3 coatings, of different thickness (30–350 µm), deposited onto stainless steel substrates by atmospheric plasma spraying. The laser generated ultrasonic waves were in situ recorded at the epicentre using a laser heterodyne interferometer. The acoustic waveforms were correlated with the interaction between the pulsed laser radiation and the coated metal, taking into account …
Graphene and graphene oxide on Ir(111) are transparent to wetting but not to icing
2021
Anti-icing coatings reduce the freezing onset temperature for water by changing the chemical and physical environment at the water-substrate interface to prevent ice nucleation and growth. Graphene oxide has several attributes that make it attractive as an anti-icing coating and it has been theoretically predicted that graphene oxide has a lower freezing onset temperature than pristine graphene. Here, we test this hypothesis using carefully prepared, well-characterized graphene oxide substrates. We compare the water contact angle for graphene and graphene oxide coatings, both prepared on iridium(111) surfaces. The results show both materials to be transparent to wetting, but indicate a lowe…