A5060056598- Semiconductor materials and devices
- Silicon Carbide Semiconductor Technologies
- Thin-Film Transistor Technologies
- Ion-surface interactions and analysis
- Graphene research and applications
- Advancements in Semiconductor Devices and Circuit Design
- Electrocatalysts for Energy Conversion
- Copper Interconnects and Reliability
- Integrated Circuits and Semiconductor Failure Analysis
- Fuel Cells and Related Materials
- Electronic and Structural Properties of Oxides
- Silicon and Solar Cell Technologies
- Corrosion Behavior and Inhibition
- Semiconductor materials and interfaces
- Electrochemical Analysis and Applications
- Silicon Nanostructures and Photoluminescence
- Advanced ceramic materials synthesis
- MXene and MAX Phase Materials
- Anodic Oxide Films and Nanostructures
- Metal and Thin Film Mechanics
- Mesoporous Materials and Catalysis
- 2D Materials and Applications
- Electron and X-Ray Spectroscopy Techniques
- Diamond and Carbon-based Materials Research
- Graphene and Nanomaterials Applications
Universidade Federal do Rio Grande do Sul
2015-2024
Instituto de Física La Plata
2016
University of Waterloo
2013-2014
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2004-2006
Université Paris-Sud
2000-2006
Université Paris Cité
2000-2006
Instituto de Tecnología Química
1998
We report a significant difference in the growth mechanism of Li2O2 Li–O2 batteries for toroidal and thin-film morphologies which is dependent on current rate that governs electrochemical pathway. Evidence from diffraction, electrochemical, FESEM STEM measurements shows slower densities favor aggregation lithium peroxide nanocrystallites nucleated via solution dismutase surface electrode; whereas fast rates deposit quasi-amorphous thin films. The latter provide lower overpotential charge due...
Recently, there has been a transition from fully carbonaceous positive electrodes for the aprotic lithium oxygen battery to alternative materials and use of redox mediator additives, in an attempt lower large electrochemical overpotentials associated with charge reaction. However, stabilizing or catalytic effect these can become complicated due presence major side-reactions observed during dis(charge). Here, we isolate reaction discharge by utilizing prefilled commercial peroxide crystallite...
Mesoporous nanoparticles and mixed-structure silica with existing nanometric micrometric domains on their surface were prepared using SiCl4. TiCl4 was used as precursor to obtain nano- mixed heterogeneous supported titania photocatalysts. The systems and, for comparative reasons, commercial (P25) evaluated Rhodamine B (RhB) photodegradation in deionized lake water solution. structural differences between photocatalysts observed are due the degree of particles organization, according...
The reaction of NaBH4 with RuCl3 dissolved in 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI.PF6) ionic liquid is a simple and reproducible method for the synthesis stable RuO2 nanoparticles narrow size distribution within 2-3 nm. were characterized by XRD, XPS, EDS TEM. These showed high catalytic activity either solventless or liquid-liquid biphasic hydrogenation olefins arenes under mild conditions. Hg(0) CS2 poisoning experiments XRD TEM analysis particles isolated after...
Initial stages of oxidation single-crystal, Si-faced silicon carbide were investigated using ion scattering and angle-resolved x-ray photoelectron spectroscopies. The very first products are shown to be oxycarbides (SiCxOy), while, for longer times, a mixture SiCxOy SiO2 is formed in the near-surface region growing oxide film. composition such thin films similar that reported previous investigations near-interface when thicker oxides grown on SiC.
Oxygen transport during thermal oxidation of Ge and desorption the formed oxide are investigated. Higher temperatures lower oxygen pressures promote GeO desorption. An appreciable fraction oxidized desorbs growth a GeO2 layer. The interplay between incorporation results in exchange O originally present by from gas phase throughout This process is mediated vacancies generated at GeO2/Ge interface. formation substoichiometric shown to have direct relation with
Abstract Hydrophilic and superhydrophilic surfaces of poly(sulfone) (PSU) thin films were prepared by UV irradiation in the presence O 2 or acrylic acid (AA) vapor. Treated then investigated water contact angle measurements, Fourier transformed IR spectroscopy attenuated total reflectance mode (FTIR‐ATR), X‐ray photoelectron (XPS), near‐edge absorption fine structure (NEXAFS) AFM. Water values treated PSU using either AA vapor as reactive atmosphere reached about 6° after more than 120 min...
C-containing interlayers formed between the SiC substrate and dielectric films thermally grown in O2, NO, O2 followed by annealing NO were investigated. X-ray reflectometry x-ray photoelectron spectroscopy used to determine N C incorporation interlayers, as well their mass densities thicknesses. The thickest interlayer was observed for whereas thinnest one directly evidencing that presence of decreases amount carbonaceous compounds dielectric/SiC interface region.
The nitrogen content of SiO2/SiC (4H) structures annealed in NO and N2O has been measured using nuclear reaction analysis. Samples were N15O18 or N215O at 1000 °C a static pressure 10 mbar for either 1 4 h. Annealing incorporates ∼1013 cm−2 N annealing ∼1014 cm−2, both which are an order magnitude lower than SiO2/Si. In the anneal, is predominantly incorporated near interface with atomic concentration ∼0.5%. As nitridation SiO2/Si, two features observed after anneal: surface exchange O oxide...
Changes in morphology and composition of interfacial regions thermally grown SiO2 films on SiC dry O2 induced by reoxidations were investigated using atomic force microscopy oxygen profiling. The gradual profile near the interface oxides at 1100°C evidences a transition region between SiC. Reoxidation 950°C leads to decrease thickness, while reoxidation increases thickness. These results are discussed terms role played temperature formation consumption carbon compounds SiO2∕SiC region.
The effect of using H2O2 in the thermal growth process dielectric films on n-type 4H-SiC substrates has been investigated. In comparison to conventional oxide H2O, we found that interface trap density is reduced close conduction band edge 4H-SiC. This electrical improvement correlated with decrease SiCxOy compounds at SiO2/4H-SiC region as confirmed by two independent methods. These results point use an alternative passivating agent electrically active defects.
Abstract This work aimed to study the corrosion behavior of AA2024‐T3 aluminum alloy substrates pre‐treated with 3 glicidoxypropyltrimethoxysilane (GPTMS) silane layers doped different cerium ion concentrations. The withdrawal speed from sol was 20 cm · min −1 . hybrid films were obtained by dip‐coating process and analyzed scanning electron microscopy (SEM) energy dispersive spectroscopy, Rutherford scattering spectroscopy (RBS), salt spray test, electrochemical analyses. correlation among...
Óxidos de tungstênio apresentam diferentes estequiometrias, estruturas cristalinas e morfologias.Estas características são importantes principalmente quando se deseja utilizá-los como fotocatalisadores.Neste trabalho foram obtidos filmes finos óxido por evaporação térmica sobre substratos silício (100) recobertos com ouro, aquecidos a 350 600 °C