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A buried conducting layer of metal/polymer nanocomposite was formed by very low energy gold ion implantation into polymethylmethacrylate. The conducting layer is ∼3 nm deep and of width ∼1 nm. In situ resistivity measurements were performed as the implantation proceeded, and the conductivity thus obtained as a function of buried gold concentration. The measured conductivity obeys the behavior well established for composites in the percolation regime. The critical concentration, below which the polymer remains an insulator, is attained at a dose ∼1.0×1016 atoms/cm2 of implanted gold ions.

We have measured the morphological grain sizes of nanostructured platinum and gold thin films. In previous works their electrical resistivities have been measured and a theoretical approach was proposed to explain the resistivity experimental data. It will be shown that within the framework of our theoretical approach, the morphological grain sizes play an essential role in the electrical resistivity of these metallic thin films.

The thickness dependence of the thermoelectric power of Pt films of variable thickness on a reference Au film has been determined for the case when the Pt film thickness, t, is not large compared to the charge carrier mean free path, ℓ, that is, t / ℓ. Pt film thicknesses down to 2.2 nm were investigated. We find that ΔS F = S B -S B F (where S B B and S F are the thermopowers of the Pt bulk and film, respectively) does not vary linearly as 1/t as is the case for thin film thermocouples when the film thickness is large compared to the charge carrier mean free path.Keywords: Thermopower effect; Thin-film platinum-gold thermocouples. where the scattering coefficient, p, is the fraction of energy lost by the charge carriers when reflected by the film surface. Since ρ = 1/σ, Eq. (1) can be written in terms of the resistivityAccording to Justi et al. [3] and Mayer [4], when Eq. (1) is obeyed the thermoelectric power S F of pure metal thin films with thickness t >> ℓ is given byB where U = (∂ lnℓ(E)/∂ lnE) E= ξ , E is the electron energy, ξ is the Fermi energy, and the bulk thermoelectric power S B is given bywherer k is Boltzmann's constant, T the absolute temperature, and e the electron charge.From Eqs. (2) and (3) we obtainIf Φ F and Φ B are the thermopowers of a thin-film and a thick-film of Pt with respect to a thick standard film, respectively, then [17] of the thermoelectric power of thin iron films showed the predicted 1/t thickness dependence. 3For all of the above experimental work [1,5,6,8,[14][15][16][17] The Pt and Au films were formed using a filtered vacuum arc plasma deposition method that has been fully described elsewhere [18]. Briefly, a repetitively-pulsed vacuum arc plasma gun equipped with either a Au or Pt cathode is used to form a dense metal (Au or Pt) plasma, which is then transported through a 90 o bent solenoidal magnetic field to remove any solid particulates (cathode debris) from the plasma stream. The plasma is then allowed to deposit on a substrate that is positioned near the exit of the solenoid filter. Thin film samples of different thicknesses can readily be prepared by varying the number of plasma pulses used for the deposition. For the work described here the plasma pulses were 5 ms long and the repetition rate was 1 pulse/sec. The substrates used for film deposition were ordinary glass microscope slides of dimension 25 × 75 mm 2 . The geometry used for all samples is shown in Fig. 1. The Au film strips were the same thickness for all samples, and the thickness of the Pt film was varied for the different samples. We prepared a set of samples in which the Au films were of thickness 141 ± 2 nm and the Pt films were of thicknesses from 2.2 to 166 nm. 4Importantly, we note that the vacuum arc plasma deposition method that we have used is an energetic deposition, with the depositing Pt ion flux having a directed ion energy of ~100 eV [19], resulting in films that are void free and fully dense [20].Measurements were made with the hot junction immersed in oil inside a calorimet...

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