E-MRS 2019 Spring Meeting, Nice, France, May 27 to 31, 2019. -- https://www.european-mrs.com/meetings/2019-spring-meeting

Journal Article Resistive Switching Studies of ReRAM Devices by In-Situ TEM Get access Gemma Martín, Gemma Martín MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Mireia B González, Mireia B González Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Campus UAB, 08193 Bellaterra, Spain Search for other works by this author on: Oxford Academic Google Scholar Aïda Varea, Aïda Varea MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Oriol Blázquez, Oriol Blázquez MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Giovanni Vescio, Giovanni Vescio MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Francesca Campabadal, Francesca Campabadal Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Campus UAB, 08193 Bellaterra, Spain Search for other works by this author on: Oxford Academic Google Scholar Sergi Hernández, Sergi Hernández MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Albert Cirera, Albert Cirera MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Blas Garrido, Blas Garrido MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Sònia Estradé, Sònia Estradé MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar ... Show more Francesca Peiró, Francesca Peiró MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Albert Cornet Albert Cornet MIND/IN2UB, Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 25, Issue S1, 1 February 2019, Pages 71–72, https://doi.org/10.1017/S1431927618016082 Published: 01 February 2019

APS March Meeting, Boston, MA, March 4-8, 2019. -- https://www.aps.org/meetings/meeting.cfm?name=MAR19

Thin films of Poly(3,4-ethylenedioxythiophene) complexed with Poly(styrenesulfonate) (PEDOT:PSS) on Indium Tin Oxide (ITO) have been prepared by inkjet printing technology. The process allows obtaining thin films over large areas. A relatively broad range of thicknesses can be obtained by the addition of subsequent polymer layers resembling an additive manufacturing process. The resulting inkjet PEDOT:PSS films are homogeneous as regard both electrical and mechanical properties. In spite of the characteristic parallel line topography of these inkjet printed films, both the Quantitative Nanomechanical Mapping (QNM) and the Conductive-Atomic Force Microscope (C-AFM) characterization reveal homogeneous values throughout the polymer surface regardless of the welding zones. The results discussed in this work provide the basis for the application of inkjet printing as deposition method for electrically conducting PEDOT:PSS into a large area with mechanical stability.

E-MRS Spring Meeting(2018). E-MRS Spring Meeting and Exhibit will be held in the Convention Centre of Strasbourg (France), from June 18 to 22. (2018). --.https://www.european-mrs.com/meetings/2018-fall/symposia-program https://www.european-mrs.com/materials-energy-application-emrs

Graphene oxide (GO) is currently the object of extensive research because of its potential use in mass production of graphene-based materials, but also due to its tunability which holds great promise for new nanoscale electronic devices and sensors. To obtain a better understanding of the role of GO in electronic nano-devices, the elucidation of the effects of electrical current on a single GO sheet is of great interest. In this work, in situ transmission electron microscopy is used to study the effects of the electrical current flow through single GO sheets using an scanning tunneling microscope holder. In order to correlate the applied current with the structural properties of GO, Raman spectroscopy is carried out and data analysis is used to obtain information regarding the reduction grade and the disorder degree of the GO sheets before and after the application of current.

E-MRS Spring Meeting and Exhibit. Convention Centre of Strasbourg (France), June 18-22 (2018). https://www.european-mrs.com/meetings/2018-fall/symposia-program

Nano-S&T-2017: Welcome to a New Era of Nano-Level, Hilton Fukuoka Sea Hawk, Japan, October 24- 26, 2017. -- http://www.bitcongress.com/Nano2017/ScientificProgramme9.asp

We demonstrate here that electrospray is a technique suitable for deposition carbon-based materials. It is versatile enough to be used with graphene oxide (GO), reduced graphene oxide (rGO) and carbon nanofibers (CNF), obtained by chemical methods. A detailed analysis of the effects of the dispersion properties and the main process parameters (voltage and flow rate) on the deposits quality is presented. Rigid and flexible substrates have been coated with good geometry control under ambient conditions. Thickness of GO films onto silicon substrates, optical transmittance of rGO onto fluoride doped tin oxide (FTO) coated glass substrate and electrical resistance of both, rGO and CNF films onto flexible polyamide have been correlated with deposition time. As an example of application, the manufacture of carbon nanofibers gas sensing devices deposited onto a ceramic platform and flexible polyimide by means of electrospray technique are shown.

ABSTRACTSingle‐walled carbon nanotubes (SWCNT)/expanded graphite (EG)/poly(trimethylene terephthalate) (PTT) hybrid nanocomposites were prepared via in situ polymerization. Raman spectroscopy and scanning electron microscopy (SEM) were employed to determine both, purity and morphology of the nanofillers and the dispersion of nanotubes and nanosheets. The electrical and optical properties of thin polymer films based on both “single” nanocomposites and hybrid nanocomposites were studied. For PTT/SWCNT nanocomposites, results confirmed that films optical transmittance decreases as the concentration of SWCNT increases, attaining almost no optical transmittance for 0.3 wt % of nanofiller. Conversely, the electrical conductivity of nanocomposites was found to increase by increasing the nanofiller amount and the σdc values indicate that percolation occurs at a very low SWCNT content (around 0.05 wt %). In the case of PTT/SWCNT + EG nanocomposites, when the content of SWCNT is 0.05%, the hybrid system presents lower conductivity than that corresponding to the “single” nanocomposite. The incorporation of additional EG to the PTT/SWCNT nanocomposite has a small effect on the electrical conductivity but inhibits the transparency of the system. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44370.

In order to increase the versatility of additive manufacturing multimaterial processes, a hybrid system has been developed, which is capable of combining 3D printing technology by DLP (Digital Light Processing) with a two-dimensional Drop-on-Demand Inkjet printing system. Through DLP technology based on digital micromirror devices (DMDs) it is possible to build up 3D geometries layer-by-layer using polymerization of photosensitive resins. Concurrently, while the construction process is performed, the InkJet printing system is used to deposit tiny drops of conductive inks on the substrate generated, which will thus constitute an electric circuit embedded within the three dimensional structure. On the other hand, photosensitive resins have been filled with Low Temperature Co-firing Ceramic (LTCC) particles, in order to modify the basis properties of the part by using sinterizable slurries. Finally the challenges in the sintering process for achieving functional parts are discussed and a few prototypes have been built in order to validate this technology. (C) 2017 The Authors. Published by Elsevier B.V.

One dimensional (1D) nanostructures offer a promising path towards highly efficient heating and temperature control in integrated microsystems. The so called self-heating effect can be used to modulate the response of solid state gas sensor devices. In this work, efficient self-heating was found to occur at random networks of nanostructured systems with similar power requirements to highly ordered systems (e.g. individual nanowires, where their thermal efficiency was attributed to the small dimensions of the objects). Infrared thermography and Raman spectroscopy were used to map the temperature profiles of films based on random arrangements of carbon nanofibers during self-heating. Both the techniques demonstrate consistently that heating concentrates in small regions, the here-called "hot-spots". On correlating dynamic temperature mapping with electrical measurements, we also observed that these minute hot-spots rule the resistance values observed macroscopically. A physical model of a random network of 1D resistors helped us to explain this observation. The model shows that, for a given random arrangement of 1D nanowires, current spreading through the network ends up defining a set of spots that dominate both the electrical resistance and power dissipation. Such highly localized heating explains the high power savings observed in larger nanostructured systems. This understanding opens a path to design highly efficient self-heating systems, based on random or pseudo-random distributions of 1D nanostructures.

Raman spectra of graphene oxide and thermally reduced graphene oxide were analyzed in order to relate spectral parameters with the Structural properties. The chemical composition of different graphene oxides was determined by organic elemental analysis, and the microstructure of nanocrystals was analyzed by X-ray diffraction. We find five reported bands (D, D', G, D '', and D*) in the region between 1000 and 1800 cm(-1) in all spectra. The band parameters such as position, intensity ratio, and width have been related with structural properties such as oxygen content, crystallinity, and disorder degree of GO and rGO platelets. An assessment of the Validity of the Tuinstra-Koenig and Cuesta models was carried but by using the results obtained from the fit of the first-order spectra of graphene oxide derivatives at five functions: two Gaussian and three pseudo-Voigt peaks.

Magnetic vortices have generated intense interest in recent years due to their unique reversal mechanisms, fascinating topological properties, and exciting potential applications. In addition, the exchange coupling of magnetic vortices to antiferromagnets has also been shown to lead to a range of novel phenomena and functionalities. Here we report a new magnetization reversal mode of magnetic vortices in exchange coupled Ir20Mn80/Fe20Ni80 microdots: distorted viscous vortex reversal. In contrast to the previously known or proposed reversal modes, the vortex is distorted close to the interface and viscously dragged due to the uncompensated spins of a thin antiferromagnet, which leads to unexpected asymmetries in the annihilation and nucleation fields. These results provide a deeper understanding of the physics of exchange coupled vortices and may also have important implications for applications involving exchange coupled nanostructures.

1.5μm-thick molybdenum oxide films have been electrodeposited potentiostatically from 0.2M Na2MoO4 electrolyte onto indium tin oxide (ITO)/glass substrates at pH=1, 6 and 9. The influence of cetyltrimethylammonium bromide (CTAB) surfactant on films' adhesion, morphology, degree of porosity, molybdenum speciation, and crystallographic structure has been systematically investigated. The addition of CTAB (0.01M) to the bath clearly improves film adherence to the substrate, reduces cracking, and increases crystallinity. This has an impact on the physical properties of the films. In particular, both hardness (H) and Young's modulus (E) increase, as determined from nanoindentation tests. The growth of ordered arrays of molybdenum oxide submicrometer structures, including pillars and stripes, by electrodeposition onto e-beam lithographed Au/Ti/Si substrates is also reported.

Flexible electronics are attracting much interest in gas sensor field on on-site monitoring applications due to their wear ability, lightweight and low-cost production. These performances are fully accomplished by silver-based platforms, but silver corrosion represents the main drawback for the integrity of the devices. In this work, self-heating sensor platforms fabricated by screen- and inkjet-printing techniques have been developed. The reliability of both types of sensors has been tested by long-term lifetime characterization and aging tests. These tests proved that the actuation time is interrupted by silver corrosion phenomena in screen-printing devices and by hot spots in inkjet-printing ones. Appropriate solutions regarding isolation and design improvements achieved not only an increase of lifetime and reliability, but also a decrease of power consumption.

Propagation of surface acoustic waves in lithium niobate crystals with carbon nanofibers or reduced graphene oxide layers deposited by electrospray has been investigated. We show that the ambient air humidity variations affect the phase of the wave noticeably stronger than its amplitude. The response of both phase and amplitude to fast humidity changes is in the sub-second range. The capability of surface acoustic waves of monitoring the fast changes in nano-layer properties for sensing applications has been demonstrated.