Institute Microelectronica Of Madrid Cnm Csic

Tres Cantos, Spain

Institute Microelectronica Of Madrid Cnm Csic

Tres Cantos, Spain
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Beltran A.M.,University of Cádiz | Marquis E.A.,University of Oxford | Marquis E.A.,University of Michigan | Taboada A.G.,Institute Microelectronica Of Madrid Cnm Csic | And 4 more authors.
Ultramicroscopy | Year: 2011

Unambiguous evidence of ring-shaped self-assembled GaSb nanostructures grown by molecular beam epitaxy is presented on the basis of atom-probe tomography reconstructions and dark field transmission electron microscopy imaging. The GaAs capping process causes a strong segregation of Sb out of the center of GaSb quantum dots, leading to the self-assembled GaAsxSb1-x quantum rings of 20-30nm in diameter with x~0.33. © 2011 Elsevier B.V.


Molina S.I.,F. de Ciencias | Galindo P.L.,CASEM | Gonzalez L.,Institute Microelectronica Of Madrid Cnm Csic | Ripalda J.M.,Institute Microelectronica Of Madrid Cnm Csic | And 2 more authors.
Journal of Physics: Conference Series | Year: 2010

We review in this communication our contribution to the structural characterisation of semiconductor quantum dots and wires by high resolution electron microscopy, both in phase-contrast and Z-contrast modes. We show how these techniques contribute to predict the preferential sites of nucleation of these nanostructures, and also determine the compositional distribution in 1D and 0D nanostructures. The results presented here were produced in the framework of the European Network of Excellence entitled "Self-Assembled semiconductor Nanostructures for new Devices in photonics and Electronics (SANDiE)". © 2010 IOP Publishing Ltd.


Kekesi R.,Institute Microelectronica Of Madrid Cnm Csic | Martin-Becerra D.,Institute Microelectronica Of Madrid Cnm Csic | Meneses-Rodriguez D.,Institute Microelectronica Of Madrid Cnm Csic | Meneses-Rodriguez D.,CINVESTAV | And 3 more authors.
Optics Express | Year: 2015

Perforated magnetoplasmonic Au/Co/Au multilayers support both localized and propagating surface plasmon resonances. The presence of holes produces an enhancement of the magnetic field modulation of the propagating surface plasmon wavevector with respect to the isostructural continuous film in the spectral region corresponding to the hole associated localized plasmon resonance. This is due to the increased electromagnetic field in the surrounding area of the resonant hole, and the subsequent additional contribution to the magnetic modulation of the continuous film. This novel concept that gives rise to enhanced magnetic field induced nonreciprocal effects can be of interest in the development of innovative platforms for sensing applications, optical isolators and modulators. © 2015 OSA.


Martin J.,Institute Microelectronica Of Madrid Cnm Csic | Martin-Gonzalez M.,Institute Microelectronica Of Madrid Cnm Csic | Del Campo A.,CSIC - Institute of Ceramics and Glass | Reinosa J.J.,CSIC - Institute of Ceramics and Glass | Fernandez J.F.,CSIC - Institute of Ceramics and Glass
Nanotechnology | Year: 2012

We present a simple, efficient, and high-throughput methodology for the fabrication of ordered nanoporous polymeric surfaces with areas in the range of cm 2. The procedure is based on a two-stage replication of a master nanostructured pattern. The process starts with the preparation of an ordered array of poly(tetrafluoroethylene) (PTFE) free-standing nanopillars by wetting self-ordered porous anodic aluminum oxide templates with molten PTFE. The nanopillars are 120nm in diameter and approximately 350nm long, while the array extends over cm 2. The PTFE nanostructuring process induces surface hydrocarbonation of the nanopillars, as revealed by confocal Raman microscopy/spectroscopy, which enhances the wettability of the originally hydrophobic material and facilitates its subsequent use as an inverse pattern. Thus, the PTFE nanostructure is then used as a negative master for the fabrication of macroscopic hexagonal arrays of nanopores composed of biocompatible poly(vinylalcohol). In this particular case, the nanopores are 130-140nm in diameter and the interpore distance is around 430nm. Features of such characteristic dimensions are known to be easily recognized by living cells. Moreover, the inverse mold is not destroyed in the pore array demolding process and can be reused for further pore array fabrication. Therefore, the developed method allows the high-throughput production of cm 2-scale biocompatible nanoporous surfaces that could be interesting as two-dimensional scaffolds for tissue repair or wound healing. Moreover, our approach can be extrapolated to the fabrication of almost any polymer and biopolymer ordered pore array. © 2012 IOP Publishing Ltd.


Herreno-Fierro C.A.,University of Los Andes, Colombia | Herreno-Fierro C.A.,University Distrital C | Patino E.J.,University of Los Andes, Colombia | Armelles G.,Institute Microelectronica Of Madrid Cnm Csic | Cebollada A.,Institute Microelectronica Of Madrid Cnm Csic
Applied Physics Letters | Year: 2016

The optical, ellipsometric, and magneto-optical surface sensitivity to dielectric environment of magnetoplasmonic nanodisks is experimentally studied. Here, the shift of the corresponding spectral structures as a function of the thickness of a coating SiO2 layer is characterized. Our results reveal that the so called pseudo-Brewster Angle, easily identified in the ellipsometric phase (Δ) spectrum, is up to four times more sensitive than the conventional features used in surface plasmon resonance based sensors. These results highlight the need of investigating the factual implementation of this technique to develop improved ellipsometric-phase based transducers for bio-chemical sensing purposes. © 2016 AIP Publishing LLC.


Hernandez-Maldonado D.,University of Cádiz | Herrera M.,University of Cádiz | Sales D.L.,University of Cádiz | Alonso-Gonzalez P.,Institute Microelectronica Of Madrid Cnm Csic | And 5 more authors.
Applied Surface Science | Year: 2010

The compositional distribution of InAs quantum dots grown by molecular beam epitaxy on GaAs capped InAs quantum dots has been studied in this work. Upper quantum dots are nucleated preferentially on top of the quantum dots underneath, which have been nucleated by droplet epitaxy. The growth process of these nanostructures, which are usually called as quantum dots molecules, has been explained. In order to understand this growth process, the analysis of the strain has been carried out from a 3D model of the nanostructure built from transmission electron microscopy images sensitive to the composition. © 2010 Elsevier B.V. All rights reserved.


Hernandez-Maldonado D.,University of Cádiz | Herrera M.,University of Cádiz | Alonso-Gonzalez P.,Institute Microelectronica Of Madrid Cnm Csic | Gonzalez Y.,Institute Microelectronica Of Madrid Cnm Csic | And 8 more authors.
Microscopy and Microanalysis | Year: 2011

We show in this article that it is possible to obtain elemental compositional maps and profiles with atomic-column resolution across an InxGa 1?xAs multilayer structure from 5th-order aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The compositional profiles obtained from the analysis of HAADF-STEM images describe accurately the distribution of In in the studied multilayer in good agreement with Muraki's segregation model [Muraki, K., Fukatsu, S., Shiraki, Y. & Ito, R. (1992). Surface segregation of In atoms during molecular beam epitaxy and its influence on the energy levels in InGaAs/GaAs quantums wells. © Microscopy Society of America 2011.


PubMed | Institute Microelectronica Of Madrid Cnm Csic
Type: Journal Article | Journal: Nanotechnology | Year: 2011

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 of the accumulated stress at the epitaxial heterostructure produces a controlled beam breakage at the previously defined beam notch. After the breakage, the relaxed strain is proportional to the beam length, allowing nanogap size control. The starting structure is similar to a mechanically adjustable break junction but the stress causing the breakage is, in this case, built into the beam. This novel technique should be useful for molecular-scale electronic devices.


PubMed | Institute Microelectronica Of Madrid Cnm Csic
Type: Journal Article | Journal: Nanotechnology | Year: 2012

We present a simple, efficient, and high-throughput methodology for the fabrication of ordered nanoporous polymeric surfaces with areas in the range of cm(2). The procedure is based on a two-stage replication of a master nanostructured pattern. The process starts with the preparation of an ordered array of poly(tetrafluoroethylene) (PTFE) free-standing nanopillars by wetting self-ordered porous anodic aluminum oxide templates with molten PTFE. The nanopillars are 120 nm in diameter and approximately 350 nm long, while the array extends over cm(2). The PTFE nanostructuring process induces surface hydrocarbonation of the nanopillars, as revealed by confocal Raman microscopy/spectroscopy, which enhances the wettability of the originally hydrophobic material and facilitates its subsequent use as an inverse pattern. Thus, the PTFE nanostructure is then used as a negative master for the fabrication of macroscopic hexagonal arrays of nanopores composed of biocompatible poly(vinylalcohol). In this particular case, the nanopores are 130-140 nm in diameter and the interpore distance is around 430 nm. Features of such characteristic dimensions are known to be easily recognized by living cells. Moreover, the inverse mold is not destroyed in the pore array demolding process and can be reused for further pore array fabrication. Therefore, the developed method allows the high-throughput production of cm(2)-scale biocompatible nanoporous surfaces that could be interesting as two-dimensional scaffolds for tissue repair or wound healing. Moreover, our approach can be extrapolated to the fabrication of almost any polymer and biopolymer ordered pore array.


PubMed | Institute Microelectronica Of Madrid Cnm Csic
Type: Journal Article | Journal: Small (Weinheim an der Bergstrasse, Germany) | Year: 2010

The sticking effect between hydrophilic surfaces occurring at increasing relative humidity (RH) is an everyday phenomenon with uncountable implications. Here experimental evidence is presented for a counterintuitive monotonous decrease of the capillary adhesion forces between hydrophilic surfaces with increasing RH for the whole humidity range. It is shown that this unexpected result is related to the actual shape of the asperity at the nanometer scale: a model based on macroscopic thermodynamics predicts this decrease in the adhesion force for a sharp object ending in an almost flat nanometer-sized apex, in full agreement with experiments. This anomalous decrease is due to the fact that a significant growth of the liquid meniscus formed at the contact region with increasing humidity is hindered for this geometry. These results are relevant in the analysis of the dynamical behavior of nanomenisci. They could also have an outstanding value in technological applications, since the undesirable sticking effect between surfaces occurring at increasing RH could be avoided by controlling the shape of the surface asperities at the nanometric scale.

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