Manuel Dominguez

Manuel Dominguez
Universidad de Cádiz | UCA · Department of Condensed Matter Physics

PhD

About

105
Publications
13,937
Reads
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1,209
Citations
Additional affiliations
January 1995 - December 1995
University of Maryland, College Park
Position
  • PostDoc Position
December 1992 - March 2020
Universidad de Cádiz
Position
  • Professor (Associate)
Education
January 1988 - June 1993
Universidad de Cádiz
Field of study
  • Physics
October 1981 - June 1986
Universidad de Cádiz
Field of study
  • Chemistry

Publications

Publications (105)
Article
Full-text available
Electrolyte material optimization is crucial for electrochemical energy storage devices. The specific composition and structure have an impact on conductivity and stability, both of which are essential for efficient device performance. The effects of controlled incorporation of TiO2 into a Yttria-Stabilized Zirconia (YSZ) electrolyte using the atom...
Article
Full-text available
Copper nitride (Cu3N), a metastable poly-crystalline semiconductor material with reasonably high stability at room temperature, is receiving much attention as a very promising next-generation, earth-abundant, thin film solar light absorber. Its non-toxicity, on the other hand, makes it a very attractive eco-friendly (greener from an environmental s...
Article
Carbon fibre reinforced polymers (CRFP) are extensively used in many industrial applications thanks to its mechanical properties and its low weight. Nevertheless, the orthotropic character of CRFP highly reduces its applications. The transversal electrical conductivity in CRFP is two orders poorer than in the longitudinal direction. To improve thei...
Article
Full-text available
The usage of conjugated materials for the fabrication of foams intended to be used as therapeutic scaffolds is gaining relevance these days, as they hold certain properties that are not exhibited by other polymer types that have been regularly used until the present. Hence, this work aims to design a specific supercritical CO2 foaming process that...
Article
Vanadium dioxide is a promising material for application in smart windows, which undergoes a metal-to-insulator transition, MIT, at 68°C accompanied by a structural phase transformation, SPT, from VO2(M1) to VO2(R). In this study, two VO2 thin films, one W⁶⁺-doped and another one undoped, have been prepared. Both were synthesized via polymer-assist...
Article
Full-text available
The optical properties of 5wt% Fe3O4-TiO2 thin films were evaluated in detail with the aim of proposing a mechanism for solar photocatalytic processes and highlighting the advantages over the use of bare TiO2. The results showed that the incorporation of 5wt% Fe3O4 enhanced the optical properties by a redshift to a wavelength in the visible range,...
Article
Full-text available
The ''Gold Dust Defect'' affects the surface quality of AISI 430 ferritic stainless steels. However, there is a very limited number of studies focusing on it. To better understand its nature, we have combined several techniques, such as x- ray photoelectron spectroscopy, atomic force microscopy, and transmission electron microscopy, in order to ext...
Article
This work reports on the design and preparation of composites based on a high impact acrylonitrile‐butadiene‐styrene polymer matrix filled either with aluminium microparticles or graphite nanoplatelets. A surfactant and tin were further added to improve the dispersion and adhesion of the fillers in an attempt to improve the conductivity of the mate...
Article
In this paper, two Schottky structures of Au/n-GaAs (sample A) and Au/0.8 nm-GaN/n-GaAs (sample B) were fabricated and electrically characterized by current–voltage measurements at different temperatures. Two models, a classical one and another previously proposed named Helal model ref (Helal et al. Eur Phys J Plus, 135:1–14, 2020). Both the models...
Article
Full-text available
Vanadium dioxide (VO2) is widely recognized as a thermochromic material with great potential for application in smart glazing for energy-efficient buildings. The monoclinic (M1) VO2 phase undergoes a first-order reversible phase transition from the semiconductor to the rutile metallic state. In this study, an M1 VO2 porous film was synthesized via...
Article
Full-text available
An original, simple and cost-effective oxidation strategy to attain thermochromic vanadium dioxide thin films is reported. This two-step procedure comprises the initial deposition of DC magnetron-sputtered vanadium or vanadium oxide films by the combination of glancing angle deposition and, if needed, reactive gas pulsing process, followed by fast...
Article
Au/0.8 nm–GaN/n–GaAs Schottky diodes were manufactured and electrically characterized over a wide temperature range. As a result, the reverse current Iinv increments from 1 × 10−7 A at 80 K to about 1 × 10−5 A at 420 K. The ideality factor n shows low values, decreasing from 2 at 80 K to 1.01 at 420 K. The barrier height qϕb grows abnormally from 0...
Article
Large contact resistance at metal-substrate/ZnO heterostructure interfaces prevents achieving highly efficient device performance. Herein, we present a systematic study on the effect of Ni-doping in the reduction of the Schottky contact barrier at metal-substrate/ZnO heterostructure. To this end, Ni-doped zinc oxide (Ni:ZnO) thin films were deposit...
Article
Full-text available
Growing ultrathin nanogranular (NG) metallic films with continuously varying thickness is of great interest for studying regions of criticality and scaling behaviors in the vicinity of quantum phase transitions. In the present work, an ultrathin gold plasmonic NG film was grown on a sapphire substrate by RF magnetron sputtering with an intentional...
Article
Full-text available
We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to...
Article
Full-text available
Stereolithography is an additive manufacturing technology commonly used to build either prototypes or final parts. Nevertheless, the manufacture of structural parts has been ruled out owing to the poor mechanical properties of conventional UV-curable resins. Moreover, the inventory of available commercial resins is still limited and they exhibit lo...
Article
Full-text available
In this work a one-pot synthesis of water soluble glutathione capped magnetite nanoparticles is reported. The magnetic characterization of the samples shows the expected superparamagnetic behavior, but a wide range of blocking temperatures is found, since the size and interparticle interactions are very sensitive to preparation conditions. These pr...
Article
Full-text available
In this work, we have grown nanostructured vanadium dioxide (VO2) thin films by a spray pyrolysis coating method on glass pre-heated substrates at 450 °C and studied their optical and electronic properties. As-prepared film structure and morphology, with a thickness of ~ 400 nm, were examined by X-ray diffraction, Raman spectra, and atomic force mi...
Article
Full-text available
We present an ellipsometric analysis to model the order-disorder transition in nano-granular gold embedded in a silica matrix (Au-SiO2). The optical measurements were performed by means of Reflection Spectroscopic Ellipsometry (RSE) over the spectral wavelength range 300–2500 nm. Upon thermal annealing of Au-SiO2 in the temperature range of 200 to...
Poster
Full-text available
En este trabajo se describe la estructura del proyecto SUNRAS, las fases del proyecto y los estudios de investigación que se están llevando a cabo.
Article
Full-text available
This work presents results in the field of advanced substrate solutions in order to achieve high crystalline quality group-III nitrides based heterostructures for high frequency and power devices or for sensor applications. With that objective, Low Temperature Co-fired Ceramics has been used, as a non-crystalline substrate. Structures like these ha...
Article
Full-text available
The microstructure and optical properties of TiO2 thin films, prepared by the sol-gel dip coating technique on glass substrates, were inspected. After deposition, the films were annealed at several temperatures in the 400–850 °C range and the resulting nanostructured films were studied by different techniques showing that their structural and optic...
Poster
Full-text available
The optical response of different types of multilayered nanostructures was studied by means of spectroscopic ellipsometry. A variable angle spectroscopic rotating analyzer ellipsometer, J.A. Woollam V-VASE, was used to measure the ellipsometric angles, amplitude ratio (Ψ) and phase differences (Δ) between the reflected polarized light p and s compo...
Article
Full-text available
Discontinuous multilayer (DML) thin films, which consist of nano-granular metals (NGMs) embedded in a dielectric matrix, have attracted significant interest as engineered plasmonic metamaterials. In this study, a systematic layer-by-layer deposition of three-dimensional sub-wavelength periodic plasmonic DML structures via the radio frequency sputte...
Article
We have optimized a synthetic method for the preparation of water soluble CdTe quantum dots (QDs), capped with glutathione (GSH) molecules, chemically bound to the nanoparticle surface (GSH-CdTe QDs). These QDs have been prepared by a co-precipitation reaction, in the presence of GSH. Modulating the temperature (from 90 to 145 °C) and the heating t...
Article
We report on the optical properties in the dielectric regime of gold nanostructured granular metal thin films fabricated through sputter deposition with a composite target at room temperature and over a wide photon energy range (0.62–4.13 eV) by means of Spectroscopic Ellipsometry. The thickness and the films effective optical constants are success...
Article
The design and construction of the working prototype of a device to measure the magnetic field induced by a conducting wire as well as the current that induces this field, based on the magneto-optical Faraday effect, is described in this work. The transducer element is a nanocomposite material made up of maghemite nanoparticles embedded in a porous...
Article
Full-text available
The universality of the ac electrical transport in granular metals has been scarcely studied and the actual mechanisms involved in the scaling laws are not well understood. Previous works have reported on the scaling of capacitance and dielectric loss at different temperatures in Co-ZrO2 granular metals. However, the characteristic frequency used t...
Article
Full-text available
The ac response in the dielectric regime of thin films consisting of Pd nanoparticles embedded in a ZrO2 insulating matrix, fabricated by co-sputtering, was obtained from impedance spectroscopy measurements (11 Hz–2 MHz) in the temperature range 30–290 K. The response was fitted to an equivalent circuit model whose parameters were evaluated assumin...
Article
Full-text available
Graphene quantum dots (GQDs) were prepared using a top-down approach with a green microwave-assisted hydrothermal synthesis from ultrathin graphite, previously ultrasound delaminated. Results obtained by transmission electron microscopy and atomic force microscopy indicate that the so-fabricated GQDs are plates with 6 nm of average diameter, mostly...
Article
The present work is focused on the evaluation and characterization of the Magnetooptical Faraday Effect (MOFE) of sol–gel processed composites consisting of maghemite iron oxide nanoparticles embedded in a silica xerogel matrix. These materials are of great interest mainly for magnetic-field sensing applications because of their high MOFE response,...
Article
Full-text available
The tunneling differential conductance of Pd-ZrO2 thin granular films prepared by RF sputtering has been measured. We found that the temperature dependence of $G(V,T)$ at zero bias $[G(0,T)\propto \exp(-\sqrt{\frac{U}{k_BT}\,})]$ reveals the presence of thermally assisted tunneling. The dependence of differential conductance on applied voltage show...
Preprint
Bulk monolithic samples of {\gamma}-Fe2O3/SiO2 composites with different iron oxide/silica ratios have been prepared by the sol-gel technique. Iron oxide nanoparticles are obtained in-situ during heat treatment of samples and silica matrix consolidation. Preparation method was previously optimized to minimize the percentage of antiferromagnetic {\a...
Conference Paper
Full-text available
20121004_Au and Ag nanoparticle-doped-TiO2 thin films: structural and optical characterization and antireflective properties
Article
Full-text available
Advances in the life sciences are now closely linked to the availability of new experimental tools that allow for the manipulation of biomolecules and the study of biological processes at the molecular level. In this context, we have optimized a synthesis process to obtain glutathione‐capped fluorescent CdS nanoparticles to specifically detect Glut...
Article
Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seem...
Article
Glutaraldehyde (GA) is widely used as a crosslinker to immobilize enzymes, for examples in biosensors, but often causes partial denaturation. We find that the proper use of poly(ethylene glycol) (PEG) during the crosslinking process can fully preserve the native state and activity of horseradish peroxidase (HRP). An amperometric biosensor was devel...
Article
Full-text available
An increasing number of promising applications for future technology is arising from size constraints in nanoparticles (NPs) and from the chemical manipulation of their surfaces. In this work, we analyse the finite-size and surface effects on polyacrylic acid-coated Fe(3)O(4) NPs and oleic acid-coated gamma-Fe(2)O(3) NPs by studying their magnetiza...
Article
Full-text available
The effects of iron concentration in the matrix structure of monolithic γ-Fe2O3/SiO2 nanocomposites with different thermal processing have been studied by means of X-ray diffraction, Fourier transform infrared spectroscopy, temperature programmed decomposition-mass spectrometry and thermogravimetric analysis. The chemical changes occurring during t...
Article
Evolution of static magnetic properties of a set of enhanced γ-Fe2O3/SiO2 nanocomposites with different iron concentration has been studied on the basis of their corresponding hysteresis loops, zero-field/field-cooled (ZFC/FC) magnetization curves and transmission electron microscopy images. The lack of coercivity in all compositions, as well as th...
Article
In this paper we investigate the nano-characterization of polypyrrole (Ppy) thin film electro-synthesized on highly oriented pyrolitic graphite (HOPG) with and without horseradish peroxidase enzyme (HRP) using Atomic force microscopy (AFM) performed in contact mode and fluid cell with electrolyte and potential control (ECAFM). In situ electro-synth...
Article
A representative nanocomposite made of ferrimagnetic [gamma]-Fe2O3 and antiferromagnetic [alpha]-Fe2O3 nanoparticles with estimated weight fractions of ~90 and ~10%, respectively, and grown in transparent silica xerogels has been characterized by Mössbauer spectroscopy with respect to the temperature. The changes of the hyperfine parameters of the...
Article
A description of the growth processes of maghemite ([gamma]-Fe2O3) nanoparticles in a silica matrix (SiO2) synthesized under a classic sol-gel method is proposed in order to explain the observed magnetic behavior at different stages of the sample heat treatment. Analytical electron microscopy studies reveal the appearance of large iron oxide aggreg...
Article
Full-text available
The preparation and processing of maghemite-silica gel nanocomposites have been investigated in order to maximize their magneto-optical response for magnetic field sensing applications. In situ precipitation of maghemite nanoparticles from an iron salt precursor during the sol-gel processing of the silica matrix has been carried out while controlli...
Article
A third-generation biosensor based on HRP and a Sonogel–Carbon electrode has been fabricated with the aim of monitoring hydrogen peroxide in aqueous media via a direct electron transfer process. The redox activity of native HRP, typical of thin-layer electrochemistry, was observed. The charge coefficient transfer, α, and the heterogeneous electron...
Article
Bulk monolithic samples of ?-Fe2O3/SiO2 composites with different iron oxide/silica ratios have been prepared by the sol-gel technique. Iron oxide nanoparticles are obtained in-situ during heat treatment of samples and silica matrix consolidation. Preparation method was previously optimized to minimize the percentage of antiferromagnetic ?-Fe2O3 an...
Article
Direct electrochemistry of Trametes versicolor Laccase (LAC) was found at a Sonogel-Carbon electrode. The bioamplification, performed by dual immobilization of this enzyme and Mushroom Tyrosinase (TYR), of the bio-electrocatalytic reduction of O(2) was investigated. The calculated alpha transfer coefficients were 0.64 and 0.67, and the heterogeneou...
Article
The present work has been focused on the interpretation of variable temperature ferromagnetic resonance spectra of mixed ?/?-Fe2O3-SiO2 nanocomposites, combined with previously reported magnetization and electron microscopy results. These materials have been shown to exhibit very promising properties for applications as magneto-optical sensors. Sol...
Article
Full-text available
In the context of current Narratology, a novel can be regarded as an information generator system. This information can be symbolically and numerically codified and, subsequently, studied by nonlinear characteristic geometrical methods. Using this approach, geometric structures underlying the narrative discourse become evident. In this work, using...
Article
A biosensor based on the bi-immobilization of laccase and tyrosinase phenoloxidase enzymes has been successfully developed. This biosensor employs as the electrochemical transducer the Sonogel-Carbon, a novel type of electrode developed by our group. The immobilization step was accomplished by doping the electrode surface with a mixture of the enzy...
Article
We report the first measurement of giant magnetoresistance at 10 GHz in a bulk ceramic sample of Nd0.7Sr0.3MnO3. From the surface resistance data, we deduce that the magnetoresistance, [μW(0)−μW(B)]/μW(0) at 1.2 T, has a peak value of approximately 90% at 215 K. The microwave studies are supplemented by data on low-field (≤ 3.5 mT) d.c. magnetizati...
Article
The present work has been focused on the interpretation of variable temperature ferromagnetic resonance spectra of mixed ?-Fe2O3 and ?-Fe2 O3-SiO2 nanocomposites, combined with previous magnetization and electron microscopy results. These materials have been shown to exhibit very promising applications as magneto-optical sensors. Sol-gel processing...
Article
Structural characteristics an cyclic voltammetry of three amperommetric biosensors based on immobilization of tyrosinase on a Sonogel-Carbon electrode for detection of phenols are described. Cyclic voltammetry was applied to study the electrochemical behaviour of the electrode and the electrochemical reaction on the electrode surface. Scanning elec...