Ivan Fernandez-Martinez

Nano4Energy SLNE · Management

Diamond-like carbon (DLC) coatings have been the object of research interest due to properties such as excellent wear resistance, low coefficient of friction, high hardness, high elastic modulus, and biocompatibility. Despite this, DLC has poor adhesion properties, which makes it challenging to use in industrial applications. The application of DLC...

Die wear in forming high strength steels (HSS) operations causes increased die maintenance cost and scrap rate, being a major obstacle for automation industries to meet upcoming market requirements. Advanced PVD (Cathodic Arc) coatings of high thicknesses (> 15 μm) can be optimum solution from both an economic and technical point of view, compared...

This manuscript introduces and experimentally demonstrates a novel concept of selective metal ion irradiation by combining bipolar HIPIMS with conventional DC magnetron sputtering operation and simple DC biasing. The addition of the positive pulse to a conventional HIPIMS discharge accelerates the predominantly metal ions created during the negativ...

Diamond-like carbon (DLC) coatings are used due to their extraordinary tribomechanical properties, great hardness, high elastic modulus, high wear resistance, low friction coefficient and chemical inertness, which provide them with biocompatibility. Compared to other physical vapor deposition (PVD) coatings of transition nitrides and carbonitrides,...

The microstructure, mechanical properties and thermal stability of AlTiN and AlTiBN coatings grown by reactive high-power impulse magnetron sputtering (HiPIMS) have been analyzed as a function of Al/(Al+Ti) ratio, x, between 0.5 and 0.8. The coatings were predominantly formed by a face-centered cubic Ti(Al)N crystalline phase, both with and without...

The microstructure, mechanical properties and thermal stability of AlxTi1−xN and Al1−xTixBN coatings grown by reactive high-power impulse magnetron sputtering (HiPIMS) have been analyzed as a function of Al/(Al + Ti) ratio (x) between 0.5 and 0.8. The coatings were predominantly formed by a face-centered cubic Ti(Al)N crystalline phase, both with a...

Diamond-like carbon (DLC) coatings are very interesting due to their extraordinary properties; their excellent wear resistance, very low friction coefficient, great hardness, high elastic modulus or biocompatibility can be highlighted, as can their multifunctionality. Because of this, over recent decades they have been widely used in tribological a...

This article analyses two types of surface modifications: DLC coating and texturing, together with their combined effect in lubricated contacts. Surfaces were textured using contact lithography and chemical etching, whereas DLC coatings were deposited using the magnetron sputtering technique. The effect of these modifications on the friction coeffi...

During the last few decades, diamond-like carbon (DLC) coatings were widely used for tribological applications, being an effective tool for improving the performance and the useful life of different machining tools. Despite its excellent properties, among which stand out a high hardness, a very low friction coefficient, and even an excellent wear r...

The importance of coatings in engineering has been predominant throughout the development of the new industrial era. The competitiveness of the field has led to the development of better materials that achieve superior properties. The purpose of this research is evaluating the adhesion to the surfaces coated by magnetron sputtering technique. The a...

Cr-doped diamond-like carbon (Cr-DLC) films with Cr contents ranging from 3 up to 20 at. % were synthesised in a codeposition process with HiPIMS (Cr deposition) and DC-pulsed technology (C deposition). The application of HiPIMS at low frequencies was observed to significantly enhance the energy density during the Cr plasma discharge due to the int...

Based on an already tested laboratory procedure, a new magnetron sputtering methodology to simultaneously coat two-sides of large area implants (up to ~15 cm2) with Ti nanocolumns in industrial reactors has been developed. By analyzing the required growth conditions in a laboratory setup, a new geometry and methodology have been proposed and tested...

Selective solar absorbers comprised of plasmonic materials offer great flexibility in design along with a highly promising optical performance. However, the nanopattern generation, typically done with electron beam writing, is a very time-intensive process. In this work, we present a fast, scalable, and flexible method for the fabrication of plasmo...

Nanocolumnar titanium coatings have been fabricated in two sputtering systems with very different characteristics (a laboratory setup and semi-industrial equipment), thus possessing different morphologies (150 nm long columns tilted 20° from the normal and 300 nm long ones tilted 40°, respectively). These coatings exhibit similar antibacterial prop...

Gas-phase synthesis of nanoparticles with different structural and chemical distribution is reported using a circular magnetron sputtering in an ion cluster source by applying high-power impulses. The influence of the pulse characteristics on the final deposit was evaluated on Au nanoparticles. The results have been compared with the more common di...

Diamond-like Carbon (DLC) coatings were deposited by a novel HiPIMS method that incorporates positive voltage pulses at the end of the conventional HiPIMS discharge. Different positive voltage amplitudes (100, 200, 300, 400 and 500 V) were used to evaluate the effect of this operation mode on the discharge process and the mechanical properties of t...

The research aim evaluates the wear resistance of inserts for turning of tungsten carbide (WC), uncoated and coated with titanium nitride through physical vapor deposition (PVD) process by high-power impulse magnetron sputtering (HIPIMS) technique to different concentration of titanium (Ti) and nitrogen (N). The inserts were tested in turning of th...

There is an increasing interest in the generation of well-defined nanoparticles (NPs) not only because of their size-related particular properties, but also because they are promising building blocks for more complex materials in nanotechnology.Here, we will shortly introduce the gas-phase synthesis technology that has evolved rapidly in the last y...

Poor adhesion is a recurrent problem for the wider use of diamond-like carbon (DLC) coatings in industrial applications. In this work, we investigate the effectiveness of high-power impulse magnetron sputtering (HiPIMS) metal ion etching to improve the adhesion of DLC coatings on high speed steel substrates. The influence of HiPIMS pretreatment par...

en It has been demonstrated by several groups that HiPIMS is a state of the art tool for applying demanding coatings with superior film properties. The real industrial breakthrough for the HiPIMS‐technology, has not yet happened. On the other hand, the up till now available HiPIMS‐PS were mainly been up‐scaled “prototypes”, far away from industrial...

We demonstrate high optical transmission in solar cell contacts based on nanowire arrays with subwavelength spacing. The photocurrent results obtained from fabricated devices are compared with numerical simulations. The proposed contact design leads to optical losses significantly smaller than the fraction of the top surface taken up by the metalli...

Recent developments in dynamic Atomic Force Microscopy where several eigenmodes are simultaneously excited in liquid media are proving to be an excellent tool in biological studies. Despite its relevance, the search for a reliable, efficient, and strong cantilever excitation method is still in progress. Herein, we present a theoretical modeling and...

Nanostructured tungsten (nanoW) coatings have been deposited by DC magnetron sputtering. First, the influence of the sputtering power on the adhesion of the coatings to the substrate was investigated by depositing coatings at powers varying from 30 up to 220 W. Non-delaminated coatings were achieved at powers ≤50 W. Second, the influence of coating...

The X-ray spectroscopy telescope Athena has been designed to implement the science theme "the hot and energetic universe", selected by the European Space Agency as the second large mission of its Cosmic Vision program. X-IFU, one of the two interchangeable focal plane instruments of Athena, is a high resolution X-ray spectrometer made of a large ar...

The first dark characterization of a thermometer fabricated with our Mo/Au bilayers to be used as a transition edge sensor is presented. High-quality, stress-free Mo layers, whose thickness is used to tune the critical temperature (TC) down to 100 mK, are deposited by sputtering at room temperature (RT) on Si3N4 bulk and membranes, and protected fr...

Dry-wall laser inertial fusion (LIF) chambers will have to withstand strong bursts of fast charged particles which will deposit tens of kJ m⁻² and implant more than 10¹⁸ particles m⁻² in a few microseconds at a repetition rate of some Hz. Large chamber dimensions and resistant plasma-facing materials must be combined to guarantee the chamber perfor...

Mo/Au bilayers are among the most suitable materials to be used as transition-edge sensors (TES) in cryogenic microcalorimeters and bolometers, developed, among other fields, for space missions. For this purpose the thermal stability of TES at temperatures below 150 degrees C is a critical issue. We report on the dependence of functional properties...

The emission properties of lateral and vertical QD pairs grown on GaAs nanoholes are investigated. Vertical QD pairs with different size asymmetry have been fabricated controlling the bottom QD size independently of the areal density. The emission of individual pairs is dominated by spectral diffusion effects and charge instabilities induced by the...

Molybdenum is a low Tc, type I superconductor whose fundamental properties are poorly known. Its importance as an essential constituent of new high performance radiation detectors, the so-called transition edge sensors (TESs) calls for better characterization of this superconductor, especially in thin film form. Here we report on a study of the bas...

We investigate the electronic and optical properties of InAs double quantum dots grown on GaAs (001) and laterally aligned along the [110] crystal direction. The emission spectrum has been investigated as a function of a lateral electric field applied along the quantum dot pair mutual axis. The number of confined electrons can be controlled with th...

We have studied the lateral coupling between InAs/GaAs quantum dot pairs embedded in a field-effect structure. Quantum dot pairs and molecules have been identified by the correlated evolution of the Coulomb blockade features of each QD in the pair. This behaviour is largely distorted in the presence of resonant coupling states in the QD molecule. S...

We report on the structural and electrical characterization of Mo thin films deposited at room temperature by RF magnetron sputtering. The effect of RF power on the morphology and residual stress of the films is analyzed. The films are under compressive stress and consist of densely packed columns with a lateral size on the order of 20 nm. The stre...

We have fabricated an array of closely spaced quantum dashes starting from a planar array of self-assembled semiconductor quantum wires. The array is embedded in a metallic nanogap which we investigate by micro-photoluminescence as a function of a lateral electric field. We demonstrate that the net electric charge and emission energy of individual...

An actuation mode is presented to drive the mechanical oscillation of cantilevers for dynamic atomic force microscopy. The method is based on direct mechanical excitation of the cantilevers coated with amorphous Fe-B-N thin films, by means of the film magnetostriction, i.e., the dimensional change in the film when magnetized. These amorphous magnet...

We report on the fabrication and characterization of Mo films, Mo/Au and Mo/Cu bilayers for Transition Edge Sensors (TES). The fabrication conditions (at room temperature) have been varied to achieve layers with the required properties for TES applications. The dependence of their functional properties (i.e. electrical resistivity and superconducti...

A nanogap fabrication process using strained epitaxial III-V beams is reported. The process is highly reproducible, allowing parallel fabrication and nanogap size control. The beams are fabricated from MBE-grown (GaAs/GaP)/AlGaAs strained heterostructures, standard e-beam lithography and wet etching. During the wet etching process, the relaxation o...

In situ stress measurements during sputtering deposition of amorphous Fe ₈₀ B ₂₀ films are used to control their stress and magnetoelastic properties. The substrate curvature induced by the deposited film is measured optically during growth and quantitatively related to the deposition induced accumulated stress. The resulting...

This work presents a selective ultraviolet (UV)-ozone oxidation-chemical etching process that has been used, in combination with laser interference lithography (LIL), for the preparation of GaAs patterned substrates. Further molecular beam epitaxy (MBE) growth of InAs results in ordered InAs/GaAs quantum dot (QD) arrays with high optical quality fr...

The structural, magnetic and magnetoelastic properties of Fe–B–N amorphous films, sputtered from a Fe80B20 target, in a mixture of argon and nitrogen gas, are studied for different nitrogen partial pressures. Nitrogen incorporates into the film preserving the amorphous structure, and modifying magnetic properties. The amount of nitrogen that incorp...

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Aplicada . Fecha de lectura: 29-11-08 Bibliogr.: 132-133