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We have fabricated and examined several Al single electron transistors whose small islands were positioned on top of a counter electrode and hence did not come into contact with a dielectric substrate. The equivalent charge noise figure of all transistors turned out to be surprisingly low, (2.5 - 7)*10E-5 e/sqrt(Hz) at f = 10 Hz. Although the lowest detected noise originates mostly from fluctuations of background charge, the noise contribution of the tunnel junction conductances was, on occasion, found to be dominant.Comment: 4 pages of text with 1 table and 5 figure

In this paper we implement and test a new approach for the description of the electrochemical data (cyclic voltammetry and chronoamperometry) for phase transforming intercalation electrode materials. This approach assumes the rate-limiting step being associated with the slow nucleation of a new phase in the material particles. As a test model system, we used LiFePO 4 material. It is shown that all the electrochemical data for LiFePO 4 can be self-consistently described assuming a slow nucleation step with only minor influence of ionic diffusion and interfacial charge transfer kinetics on the intercalation rates. The developed formalism allows for a reliable diagnostics of the reaction rate control regime as well as for the extraction of information on the pre-exponential factor and activation energy values. The electrochemical diagnostic criteria for the slow nucleation step are formulated based on the shapes of the cyclic voltammetry peaks, current transients registered under potentiostatic conditions and specific features in the impedance spectra of phase-transforming electrodes.

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