74 research outputs found
Tuning the resistive switching properties of TiO2-x films
No full textWe study the electrical characteristics of TiO2-x-based resistive switching devices fabricated with different oxygen/argon flow ratio during the oxide thin film sputtering deposition. Upon minute changes in this fabrication parameter, three qualitatively different device characteristics were accessed in the same system, namely, standard bipolar resistive switching, electroforming-free devices, and devices with multi-step breakdown. We propose that small variations in the oxygen/ argon flow ratio result in relevant changes of the oxygen vacancy concentration, which is the key parameter determining the resistive switching behavior. The coexistence of percolative or non-percolative conductive filaments is also discussed. Finally, the hypothesis is verified by means of the temperature dependence of the devices in low resistance state.Fil: Ghenzi, Néstor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. CIC nanoGUNE; EspañaFil: Rozenberg, M.J.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Université Paris Sud; FranciaFil: Llopis, R.. CIC nanoGUNE; EspañaFil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hueso, Luis E.. Universidad del País Vasco; España. Fundación Vasca para la Ciencia; EspañaFil: Stoliar, Pablo Alberto. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. CIC nanoGUNE; Españ
Thermal effects on the switching kinetics of silver/manganite memristive systems
No full textWe investigate the switching kinetics of oxygen vacancy (Ov) diffusion in La(5/8-y)Pr(y)Ca(3/8)MnO(3)-Ag (LPCMO-Ag) memristive interfaces by performing experiments on the temperature dependence of the high resistance state under thermal cycling. Experimental results are well reproduced by numerical simulations based on thermally activated Ov diffusion processes and fundamental assumptions relying on a recent model proposed to explain bipolar resistive switching in manganite-based cells. The confident values obtained for activation energies and the diffusion coefficient associated to Ov dynamics constitute a validation test for both model predictions and Ov diffusion mechanisms in memristive interfaces.Fil: Stoliar, Pablo Alberto. Cic Nanogune; España. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Sánchez, M. J.. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Patterson, Germán Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Fierens, Pablo Ignacio. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
A light-controlled resistive switching memory
No full textSketch of the configuration of a light-controlled resistive switching memory. Light enters through the Al 2O 3 uncovered surface and reaches the optically active p-Si substrate, where carriers are photogenerated and subsequently injected in the Al 2O 3 layer when a suitable voltage pulse is applied. The resistance of the Al 2O 3 can be switched between different non-volatile states, depending on the applied voltage pulse and on the illumination conditions.Fil: Ungureanu, Mariana. CIC nanoGUNE Consolider; EspañaFil: Zazpe, Raul. CIC nanoGUNE Consolider; EspañaFil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. CIC nanoGUNE Consolider; EspañaFil: Stoliar, Pablo Alberto. Comisión Nacional de Energía Atómica; Argentina. CIC nanoGUNE Consolider; EspañaFil: Llopis, Roger. CIC nanoGUNE Consolider; EspañaFil: Casanova, Felix. CIC nanoGUNE Consolider; España. Basque Foundation for Science; EspañaFil: Hueso, Luis E.. CIC nanoGUNE Consolider; España. Basque Foundation for Science; Españ
Charge Injection across Self-Assembly Monolayers in Organic Field Effect Transistors: Odd-Even Effects
No full textAlkanethiol monolayers self-assembled on the Au source and drain electrodes have been used to improve the response of organic field effect transistors by different groups in the past. Here, we investigate the role of self-assembly monolayers of chain length n, where n ranges between 3 and 18, in modulating the charge injection in pentacene field effect transistors. The charge carrier mobility μ exhibits large fluctuations correlated with odd-even n. For n 8, μ decays exponentially with an inverse decay length β=0.6 Å-1. As the morphology in the channel is invariant, we account for both the electron structure and the molecular disorder at the interface by introducing a length scale of injection as a function of the chain length. Charge injection across the interface occurs by through-bond tunneling of holes mediated by the alkanethiol layer. At short chain length, decrease of both interfacial morphological disorder and pentacene-surface interactions dominates over the increasing thickness of the alkanethiol monolayer. At long chain length, the charge injection across the alkanethiol monolayer completely governs the transistor response. The odd-even effect is ascribed to the anisotropic coupling between the alkanethiol terminal sigma bond and the HOMO level of ordered pentacene molecules. Our results show that the pentacene transistor is a sensitive gauge for probing charge transport across single monolayers, and that its response is sensitive to sub-molecular details of the interface. This work was supported by the EU-Integrated Project NAIMO (No NMP4-CT-2004-500355)
Building memristive and radiation hardness TiO2-based junctions
No full textWe study micro-scale TiO2 junctions that are suitable to be used as resistive random-access memory nonvolatile devices with radiation hardness memristive properties. The fabrication and structural and electrical characterization of the junctions are presented. We obtained a retentivity of 105 s, an endurance of 104 cycles and reliable switching with short electrical pulses (time-width below 10 ns). Additionally, the devices were exposed to 25 MeV oxygen ions. Then, we performed electrical measurements comparing pristine and irradiated devices in order to check the feasibility of using these junctions as memory elements with memristive and radiation hardness properties.Fil: Ghenzi, Néstor. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rubi, Diego. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mangano, E.. Comisión Nacional de Energía Atómica. Gerencia Química. CAC; ArgentinaFil: Gimenez, G.. Comisión Nacional de Energía Atómica. Gerencia Química. CAC; ArgentinaFil: Lell, Julián Alejandro. Comisión Nacional de Energía Atómica; ArgentinaFil: Zelcer, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia Química. CAC; ArgentinaFil: Stoliar, Pablo Alberto. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Universite de Nantes; Francia. Centre National de la Recherche Scientifique; FranciaFil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica; Argentina. Comisión Nacional de Energía Atómica. Gerencia Química. CAC; Argentin
Charge Injection across Self-Assembly Monolayers in Organic Field Effect Transistors: Odd-Even Effects
No full textWe investigate the role of self-assembly monolayers in modulating the response of organic field-effect transistors. Alkanethiol monolayers of chain length n are self-assembled on the source and drain electrodes of pentacene field-effect transistors. The charge carrier mobility mu exhibits large fluctuations correlated with odd-even n. For n = 8, mu decays exponentially with an inverse decay length beta = 0.6 A(-1). Our results show that (i) charge injection across the interface occurs by through-bond tunneling of holes mediated by the alkanethiol layer; (ii) in the long-chain regime, the charge injection across the alkanethiol monolayer completely governs the transistor response; (iii) the transistor is a sensitive gauge for probing charge transport across single monolayers. The odd-even effect is ascribed to the anisotropic coupling between the alkanethiol terminal sigma bond and the HOMO level of ordered pentacene molecules
Non-conventional metallic electrodes for organic field-effect transistors
No full textWe study micrometer-sized organic field-effect transistors with either Pd or NiFe metallic electrodes. Neither of these materials is commonly used in organic electronics applications, but they could prove to be particularly advantageous in certain niche applications such as organic spintronics. Using organic semiconductors with different carrier transport characteristics as active layer, namely n-type C60 fullerene and p-type Pentacene, we prove that Pd (NiFe) is a very suitable electrode for p- (n-) type semiconductors. In particular, we characterized devices with channel lengths in the order of the micrometer, a distance which has allowed us to evaluate the electronic behavior in a regime where the interfacial problems become predominant and it is possible to reach elevated longitudinal electric fields. Our experimental results agree well with a simple model based on rigid energy levels.Fil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. The CIC nanoGUNE Consolider; España. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gobbi, M.. The CIC nanoGUNE Consolider; EspañaFil: Llopis, Roger. The CIC nanoGUNE Consolider; EspañaFil: Stoliar, Pablo Alberto. The CIC nanoGUNE Consolider; España. Centre National de la Recherche Scientifique; Francia. Universidad Nacional de San Martín; ArgentinaFil: Casanova, Félix. Ikerbasque, Basque Foundation For Science; España. The CIC nanoGUNE Consolider; EspañaFil: Hueso, Luis E.. Ikerbasque, Basque Foundation For Science; España. The CIC nanoGUNE Consolider; Españ
HfO2 based memory devices with rectifying capabilities
No full textWe report on the fabrication and characterization of metal/insulator/metal capacitor like devices, with both rectifying and hysteretic features. Devices are formed by two junctions, Ti/HfO2 and Co/HfO2. Each junction exhibits highly repetitive hysteretic I-V curves with a sharp transition from a high to a low resistance state (3–4 orders of magnitude jump). The opposite transition (from low to high) is induced by polarity reversal. The rectifying non-crossing characteristics of the I-V branches denote their potential use as a multifunctional device, acting as a built-in rectifier and memory cell in a single device. Based on the phenomenological model description by Zazpe et al. [Appl. Phys. Lett. 103, 073114 (2013)], we propose a circuital equivalent representation supported on switchable rectifying junctions. By exploring different electrode connections, we disentangle the role of the bulk transport in HfO2 devices.Fil: Quinteros, Cynthia Paula. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zaspe, R.. CIC nanoGUNE; EspañaFil: Marlasca, F. G.. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; ArgentinaFil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Casanova, F.. CIC nanoGUNE; España. Fundación Vasca para la Ciencia; EspañaFil: Stoliar, Pablo Alberto. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Centre National de la Recherche Scientifique; Francia. Universite de Nantes; FranciaFil: Hueso, L.. Fundación Vasca para la Ciencia; España. CIC nanoGUNE; EspañaFil: Levy, Pablo Eduardo. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones no Nucleares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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