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Laser Induced-Thermionic Vacuum Arc (LTVA) technology was used for depositing uniform intermetallic CoNi thin films of 100 nm thickness. LTVA is an original deposition method using a combination of the typical Thermionic Vacuum Arc (TVA) system and a laser beam provided by a QUANTEL Q-Smart 850 Nd:YAG compact Q-switched laser with a second harmonic module. The novelty is related to the simultaneous deposition of a bi-component metallic thin film using photonic processes of the laser over the plasma deposition, which improves the roughness but also triggers the composition of the deposited thin film. Structural analysis of the deposited thin films confirms the formation of face-centered cubic (fcc) as the main phase CoNi and hexagonal Co3Ni as the minority phase, observed mainly using high-resolution transmission electron microscopy. The magneto-optical measurements suggest an isotropic distribution of the CoNi alloy thin films for the in-plan angular rotation. From the low coercive field of Hc = 40 Oe and a saturation field at 900 Oe, the CoNi thin films obtained by LTVA are considered semi-hard magnetic materials. Magnetic force microscopy reveals spherical magnetic nanoparticles with mean size of about 40–50 nm. The resistivity was estimated at ρ = 34.16 μΩ cm, which is higher than the values for bulk Co and Ni. [ABSTRACT FROM AUTHOR]

Active semiconductor layers of TiO2 were synthesized via pulsed laser deposition in He, N2, O2, or Ar to manufacture DSSC structures. As-prepared nanostructured TiO2 coatings grown on FTO were photosensitized by the natural absorption of the N719 (Ruthenium 535-bis TBA) dye to fabricate photovoltaic structures. TiO2 photoanode nanostructures with increased adsorption areas of the photosensitizer (a combination with voluminous media) were grown under different deposition conditions. Systematic SEM, AFM, and XRD investigations were carried out to study the morphological and structural characteristics of the TiO2 nanostructures. It was shown that the gas nature acts as a key parameter of the architecture and the overall performance of the deposited films. The best electro-optical performance was reached for photovoltaic structures based on TiO2 coatings grown in He, as was demonstrated by the short-circuit current (Isc) of 5.40 mA, which corresponds to the higher recorded roughness (of 44 ± 2.9 nm RMS). The higher roughness is thus reflected in a more efficient and deeper penetration of the dye inside the nanostructured TiO2 coatings. The photovoltaic conversion efficiency (η) was 1.18 and 2.32% for the DSSCs when the TiO2 coatings were deposited in O2 and He, respectively. The results point to a direct correlation between the electro-optical performance of the prepared PV cells, the morphology of the TiO2 deposited layers, and the crystallinity features, respectively. [ABSTRACT FROM AUTHOR]

Tantalum pentoxide (Ta2O5) thin films were synthesized using thermionic vacuum arc (TVA) technology. TVA is an original deposition method using a combination of anodic arc and electron gun system for the growth of thin films from solid precursors under vacuum of 10-6 Torr. The properties of the deposited Ta2O5 thin films were investigated in terms of wettability, refractive index, morphology, and structure. The surface free energy was determined by means of surface energy evaluation system indicating a hydrophilic character and the refractive index was measured by Filmetrics F20 device. The morphology was determined from bright field transmission electron microscopy (TEM) image performed by Philips CM 120 ST TEM system. It exhibits nanoparticles of 3-6 nm diameter smoothly distributed. Selected area electron diffraction pattern revealed the contrast fringes given by complex polycrystalline particles included in the amorphous film. The measured fringes could be indexed using monoclinic structure of Ta2O5. [ABSTRACT FROM AUTHOR]

The aim of this contribution is to present the properties of the nanostructured hydrogenated carbon thin films and to study their growth carried out in a special deposition technique based on Thermionic Vacuum Arc method. The Gaseous Thermionic Vacuum Arc (G-TVA) technology is an original deposition method performed in a special configuration, consisting of a heated thermionic cathode which provides an electron beam on the anode. The surface free energy was evaluated by contact angle and their optical properties were studied by Filmetrics F20 spectrometry system. Structure of the film has been investigated by Raman spectroscopy as well as the mechanical properties like hardness, wear resistance, film-substrate adhesion. The films showed two distinct Raman characteristic peaks located at 1,350 cm (D-line) and 1,550 cm (G-line), broad for Si and very sharp for glass substrates. The G-TVA enables to prepare soft (hardness ~6 GPa) or hard (~24 GPa) films. [ABSTRACT FROM AUTHOR]

The aim of this paper is to an report analysis of the different characteristics of the coatings obtained by an extension in applicability of the thermionic vacuum arc method, i.e., gaseous thermionic vacuum arc using gases as precursors, instead of solid materials. The morphology and structure of the film were investigated by transmission electron microscopy (TEM) provided by high-resolution TEM with 1.4-\\rm \AA resolution and 1.2-M magnification. [ABSTRACT FROM AUTHOR]