Stage 1 - P4
The project implementation schedule
Phase no. 1
Responsible: Dr. M. SCARISOREANU
Title: "Nanostructurated films obtained by combined laser techniques used as toxic gas sensors"
Abstract: The nanostructured films of materials with sensory properties offer major benefits: an increased sensitivity, repeatability, a reducing limit of gas detection and of working temperature for the sensory cell dimension and lower the possibility cipation complex gas sensors. Nanostructured films are obtained from nanoparticles synthesized by laser pyrolysis, followed by a physical deposition: spin coating technique or MAPLE- PLD. Regarding to the base precursors the following volatile organometallic compound has been used: tetramethyltin as tin source and for doping with other elements iron pentacarbonyl, trimetoximetil silane (SiX3Y) or cobalt tricarbonyl nitrosyl. The powders were analyzed by XRD, TEM, HREM, EDS, FTIR, Raman and SEM. Nanostructured films are analyzed by XRD, FT-IR, SEM, UV-VIS, ot AFM and electrical properties are measured by the deposition of films on substrates having electrical contacts (Au) positioned at 0.2 mm. All films deposited on Si having intrinsic electrical contacts positioned 0.4 mm are placed in oven were tested in a controlled atmosphere conditions using between 100-1000 ppm H2, CH4 or ethanol vapor, all in synthetic air and temperatures between 150 and 3500C. The electrical measurements and the response tests to traces of hydrogen indicate a sensitivity adequate to applications as nanostructured films for toxic gas sensors. Also, a set with composite nanoparticles having the core of tin oxide and silica-based coating has been performed and analyzed.
Phase no. 2
Responsible: Dr. C. POROSNICU
Title: "Morpho-structural changes in nuclear fusion related multilayer films induced by laser radiation and indirect heating"
Abstract: We suggest a study on optimum deposition conditions for W content multilayer thin films, using the thermionic vacuum arc deposition method with direct applicability in nuclear fusion. Also the effect of direct laser radiation on morphological changes induced to structures with tungsten content was detected. Also, the morphological changes as a result of ion beam indirect heating during the W content layer deposition and nitrogen and deuterium gaseous inclusions by increasing the ionization degree of magnetron plasmas were investigated.
At this stage, two multilayer structures with W, Ni and Fe respectively were obtained using TVA technique. The thickness of the thin films was 210 nm and it was obtained by layer successive deposition with 30 nm thickness of W and Ni respectively. For W+Fe+Ni structure, a direct irradiation was applied using a 2W power laser with a wavelength of 355 nm and a 20 microns spot in diameter and a 500kHz frequency to simulate the conditions met in the vicinity of the divertor wall inside a fusion reactor. The W layers with N and D gaseous inclusions were obtained by co-deposition in reactive atmosphere of Ar-D and Ar-D-N, separately, by two techniques: HiPIMS and DCMS.
As a result of the investigations carried out on the samples with W content, a change on morphological and structural properties before and after exposure to laser radiation and deuterium/ argon/ nitrogen ion beam was detected. Additional investigations are required on different substrates as Si, C and W to highlight also their influence on thin films properties with W content.
Phase no. 3
Responsible: Dr. V. DAMIAN
Title: "Cercetari privind un sistem imagistic hiperspectral ce utilizeaza un sistem dispersiv interferometric"
Phase no. 4
Responsible: Dr. N. SCARISOREANU
Title: "Laser processing of multifunctional perovskite materials for environmental and energy generation applications"
Abstract: The aim of this project’s stage was the obtaining of laser-processed nanostructures of BiFeO3 - based peroskite materials for energy or environmental applications such as persistent organic pollutants degradation. Using laser ablation of ceramic targets of BFO and doped BFO (Y, La) in liquid environments (e.g. deionised water), different nanostructure’s types have been obtained and their optical, structural and photocatalytic properties have been investigated. 2-D graphene like (BiO)2CO3 nanostructures and BiFeO3 amorphous nanoparticles have been noticed after the laser ablation in liquid of the BiFeO3 target. The photocatalytic water splitting behaviour of the obtained nanostructures has been evidenced under 1.5 AM irradiation regime. The use of laser ablation in liquid technique on perovskite materials has another reason, beyond the obtaining of nanostructure with similar or superior catalytic properties those exhibited by epitaxial thin films, namely the possibility of industrial implementation of this method.
Phase no. 5
Responsible: Dr. M. MAGUREANU
Title: "Study of the effects induced by non-equilibrium plasma on liquids"
Abstract: Electrical discharges generated at the gas-liquid interface were investigated in various configurations (dielectric barrier discharge, wire-to-plate corona discharge, corona with liquid spray). The objective consisted in the identification and quantification of the main oxidizing species formed in gas phase and in liquid phase by non-equilibrium plasma: ozone (O3), hydroxyl radicals (●OH), hydrogen peroxide (H2O2). In addition, the plasma-treated solutions were analyzed in order to detect the reaction products and to determine the efficiency of the studied method for degradation and mineralization of water pollutants.
The results obtained in this study provide insight into the chemical reactions of the oxidants generated in electrical discharges in contact with liquid with an organic pollutant (methyl paraben - MeP). Plasma treatment combined with ozonation (using O3 formed in plasma) proved effective for MeP degradation. The pollutant (initial concentration 50 mg/L) was completely eliminated after 15 minutes treatment, and the reaction rate constant is two times higher as compared to ozonation. Mineralization was also substantial in the plasma+O3 configuration: 66.5% of the total organic carbon was removed after 60 minutes treatment. Although O3 significantly accelerated MeP removal as compared to plasma treatment alone, other oxidants generated in plasma (mainly ●OH radicals) also have an essential contribution to the degradation of pollutant and to mineralization. Less ●OH radicals were detected in the MeP solution than in pure water, due to their consumption in reactions with MeP and its degradation products. The amount of H2O2 accumulated in the liquid was also influenced by the presence of MeP: depending on the concentration of organic compound, either the formation of H2O2 or its decomposition in reactions with ●OH or O3 is affected.
Phase no. 6
Responsible: Dr. B. MITU/ Dr. V. SATULU
Title: "Sinteza in plasma a structurilor planare cu alternanta de proprietati; evaluarea morfologiei si structurii chimice"
Abstract: Polytetrafluorethylene (PTFE) and amorphous hydrogenated carbon (a-C:H) thin films have been synthesized by magnetron sputtering (MS) and respectively by Plasma Enhanced Chemical Vapor Deposition (PECVD) techniques, at various values of applied RF power and deposition time.
The deposition rates have been determined for all the experimental conditions used and their dependency upon the experimental conditions were discussed. The parameters which conduct to smooth films, appropriate for realization of multilayered structures with alternate properties were identified. For the bi-component layers we proved the existence of C-F bonds, specific for PTFE layer, and C-H bonds, specific for a-C:H films in the obtained structure.