Principle of a variable capacitor based on Coulomb blockade of nanometric-size clusters

Sénéor, Pierre; Lidgi, N.; Carrey, Julian; Jaffrès, Henri; Dau, F. Nguyen Van; Friederich, A.; Fert, A.

doi:10.1209/epl/i2003-10122-3

Cited by 9 publications

(10 citation statements)

References 21 publications

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“…Two-dimensional assemblies of monodisperse metal particles with controlled size in the nanometer range present considerable interest in various applications of nanophysics: surface plasmon resonance, magnetic properties for ultrahigh density media storage, and transport properties and in electronic devices such as new flash memories . A new concept of a voltage-controlled variable capacitor has been proposed recently . These devices consist of a 2D assembly of conducting nanoparticles embedded in a thin insulating layer of a plane capacitor.…”

Section: Introductionmentioning

confidence: 99%

FTIR and XPS Study of Pt Nanoparticle Functionalization and Interaction with Alumina

et al. 2008

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Platinum nanoparticles with a mean size of 1.7 nm were synthesized by reduction in sodium acetate solution in 1,2-ethanediol. The particles were then functionalized with dodecylamine, dodecanethiol, and omega-mercapto-undecanoic acid (MUDA). Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) showed important variations of the particle surface state with functionalization whereas their structure differs only slightly. Platinum-to-sulfur charge transfer inferred from XPS of thiol-coated particles enabled the identification of the formation of Pt (delta+)-S (delta-) bonds. The native carbon monoxide (CO) at the surface of the particles was a very efficient probe for following the functionalization of the particles by FTIR. The red shift of nu(CO) accounts for the nature of the ligands at the surface of the particles and also for their degree of functionalization. Immobilization on alumina substrates of particles functionalized with MUDA was realized by immersion in colloidal solutions. Free molecules, isolated particles, and aggregates of particles interconnected by hydrogen bonds at the surface of alumina were evidenced by FTIR. With successive washings, the energy variation of the CO stretch of carbon monoxide and of carboxylic acid groups and the relative intensity nu(CH2)/nu(CO) showed that the free molecules are eliminated first, followed by aggregates and less-functionalized particles. Particles presenting a high degree of functionalization by MUDA remain and interact strongly with alumina.

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Section: Introductionmentioning

confidence: 99%

FTIR and XPS Study of Pt Nanoparticle Functionalization and Interaction with Alumina

et al. 2008

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“…[15] In these devices the variation of the capacitance is expected to depend on the particle mean size, their size distribution, and on the average density of particle distribution. [16] In order to control independently the particle mean size and their density on the tunnel barrier we chose to prepare monodisperse nanoparticles by a chemical way, to graft them on a functionalized alumina barrier by an aminosilane, and then to embed them in sputtered alumina. We show that this strategy of combining physical and chemical methods for the fabrication of this kind of nanoscale devices is advantageous both for obtaining a variable capacitance controlled by a DC applied voltage and for better understanding their electronic properties.…”

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confidence: 99%

“…Electrons are then enabled to jump back and forth from the electrode to the clusters following the added AC voltage. This leads to a capacitance variation for which the amplitude is proportional to the number of activated clusters so that the capacitance rises and falls as the voltage scans the cluster distribution (see a previous report [16] for more details of the model). We now focus on the amplitude of the capacitance variation.…”

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confidence: 99%

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Grafted 2D Assembly of Colloidal Metal Nanoparticles for Application as a Variable Capacitor

et al. 2007

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2D assemblies of monodisperse metal particles with controlled size in the nanometer range show considerable advantages in various applications of nanophysics: surface-plasmon resonance, [1] magnetic properties for ultrahigh-density media storage, [2] transport properties, [3] and for electronic devices, such as new flash memories, [4] and chemical sensors. [5] For all these solid-state applications, chemical synthesis has proven to lead to a very good control of particle size and shape. Moreover, the chemical synthesis of nanoparticles has the advantages of simplicity and low cost with respect to physical approaches. Monodisperse metal particles with a mean size tailored in the nanometer range can be produced by several chemical reactions, such as the reduction of metal salts or the decomposition of organometallic precursors.[6] Furthermore, 3D and 2D superlattices were produced from a solution of coated metal particles with surfactants after evaporation of the solvent. [7] The organization of such particle arrays depends on several factors such as the length of the alkyl chain and the nature of the surface on which the particles are deposited. Long-range ordered 2D arrays of alkanethiolate-coated gold nanoparticles have been obtained on a silicon nitride membrane, however, an excess of thiol and a slow evaporation rate are needed. [8] Even without the excess of organic molecules that may be inappropriate for some applications, it generally remains difficult to obtain reproducible 2D dense arrays of nanoparticles without the local formation of 3D aggregates. An alternative way to get 2D arrays consists of grafting nanoparticles on chemically modified surfaces. The silanization of oxide surfaces with amino-or mercapto-silane is one of the most studied methods for this purpose.[9] The covalent immobilization of gold colloids onto self-assembled monolayers (SAMs) has also been proposed.[10] Metal nanoparticles/polyelectrolyte ultrathin films can be grown as well by layer-by-layer self-assembly methods through electrostatic interactions.[11]Several studies dealing with the electrochemical properties of coated metal nanoparticles in solution showed that monodispersed alkanethiolate-protected gold nanoparticles exhibited quantized charging characteristics.[12] Such molecular-like capacitor characteristics were observed for other metals provided very small particle mean size and very low standard deviation of the size distribution were obtained.[13] Conversely, only very few studies deal with the use of metal nanoparticles prepared by chemistry for the elaboration of solid-state devices. We report a new application of 2D assemblies of metal nanoparticles in the field of electronics. We describe the elaboration and the transport properties of junctions, the structure of which is given in Figure 1. It consists of a 2D assembly of conducting nanoparticles embedded in a thin insulating layer of a plane capacitor. The left dielectric barrier is thin enough to allow a tunnel current to pass through when the DC voltage is a...

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“…The ability to produce such wires will facilitate the development of innovative electronic devices, such as variable capacitors that require Coulomb blockade-exhibiting materials. 15 The work was partially supported by the National Science Foundation ͑NER 0304413͒ and Oklahoma EPSCoR ͑EPS-132354͒. Additionally, the authors acknowledge the lithographic mask design by Sharmila Rajendran, the fabrication of the electrode-arrays by Yuguang Zhao, and the custom-milled chip mounts by Mike Lucas.…”

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confidence: 99%

Reproducible interconnects assembled from gold nanorods

Ozturk

Blackledge

Flanders

et al. 2006

Applied Physics Letters

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By using cleanroom-based lithographic procedures to produce identical electrode arrays, we have fabricated dielectrophoretic nanowires that vary in their conductance by ±10%. Transmission electron microscopy established the presence of interconnect segments composed of densely aggregated nanoparticles and of individual nanorods lying in the current-carrying path. The current-voltage profiles of these interconnects exhibited barriers to charge transport at temperatures less than ϳ225 K; furthermore, their conductances increased exponentially with temperature with an activation energy comparable to the nanorod charging energy. These results indicate that the Coulomb blockade associated with individual nanorods in the interconnects is the primary conductance-limiting feature.Dielectrophoretic assembly has emerged as a promising approach to in-parallel device fabrication that exploits the spontaneous behavior of building block populations. In dielectrophoretic assembly, the dipolar term of the interparticle potential of a colloidal dispersion is amplified, leading to the single-step assembly and interfacing of electrical interconnects with surrounding circuitry. 1,2 Several groups have used this approach to integrate nanowires, nanoparticles, and interconnects with existing electronics. 2-5 Because of the lack of reproducibility in the fabrication conditions of individually fabricated samples, there have been relatively few detailed investigations of the charge-transport properties of dielectrophoretic interconnects. 3 Here, we have employed standard photolithography to fabricate sets of identical electrode pairs on 500 m thick quartz substrates, eliminating much of the nonuniformity that hampers wire-by-wire assembly and enabling the simultaneous fabrication of up to six interconnects under identical growth conditions ͑electrode-geometry, voltage amplitude and frequency, and concentration of nanoparticle solution͒. Figure 1͑a͒ depicts the simple circuit that facilitates the targeted placement of reproducible interconnects. An optical micrograph depicts the three electrode pairs, between which three simultaneously grown interconnects span the 100 m gaps. The initial metal layer on these substrates was 100 nm of Ti onto which 500 nm of Al was deposited.We have previously demonstrated the dielectrophoretic assembly of interconnects composed of 3.7 nm diameter CdS nanoparticles. 6 However, this work 6 stopped short of revealing the structural and transport properties of these interconnects because the small size of the CdS nanoparticles inhibited resolution of the mesoscopic ͑i.e., particle level͒ structure of the interconnect. To gain this knowledge, the present study employs ϳ30 nm gold nanorods as the building blocks, easily visible with a transmission electron microscope ͑TEM͒ of moderate resolving power. We employed an established wet chemical approach to synthesize the gold nanorods. 7,8 The resulting stock solution of nanorods contained large excesses of cetyl trimethylammonium cations and bromide anions that pre...

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Principle of a variable capacitor based on Coulomb blockade of nanometric-size clusters

Cited by 9 publications

References 21 publications

FTIR and XPS Study of Pt Nanoparticle Functionalization and Interaction with Alumina

FTIR and XPS Study of Pt Nanoparticle Functionalization and Interaction with Alumina

Grafted 2D Assembly of Colloidal Metal Nanoparticles for Application as a Variable Capacitor

Reproducible interconnects assembled from gold nanorods

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