C.R. Tellier

Bio: C.R. Tellier is an academic researcher from École Normale Supérieure. The author has contributed to research in topics: Electrical resistivity and conductivity & Seebeck coefficient. The author has an hindex of 9, co-authored 14 publications receiving 241 citations.

A three-dimensional model for grain boundary resistivity in metal films

Abstract: In this work a model is proposed to express the resistivity of metal films in which two electron scattering mechanisms operate simultaneously: an isotropic background scattering and a scattering caused by three distributions of planar potentials which represent the grain boundaries. In order to describe the average properties of grain boundaries a transmission coefficient t is introduced. An interpretation of published fine-grained film data in terms of the three-dimensional model yields reasonable values of t .

Statistical model of electrical conduction in polycrystalline metals

Abstract: A new statistical model for the effect of grain boundaries on electrical conduction is proposed. The electronic transmission coefficient t is given as an exponential function of the electron path assuming that t ≈ 1. A mean free path related to grain boundary effects is then derived; the Boltzmann equation is solved using the assumption that background scattering and grain boundary scattering operate independently. The analytical expression of the total conductivity obtained in this way agrees with the Mayadas-Shatzkes equations.

Experimental determination of electronic transport parameters in monocrystalline metallic films

Abstract: New equations for the resistivity and temperature coefficient of resistivity (TCR) of monocrystalline films are derived from the theoretical predictions of the two-dimensional model previously proposed to describe the simultaneous scatterings due to the background, external surfaces and grain boundaries. It is found that the dependences of the film resistivity p Fm and TCR β Fm on the thickness a when they are plotted in the forms a p Fm and a β Fm -1 versus a should yield straight lines with slopes of p 0 and β 0 -1 respectively and an identical intercept on the ordinate of M ( t,p ). An analytical expression for M ( t,p ) as a function of the transmission coefficient t and the specularity parameter p is obtained which allows a systematic study of the changes in these parameters under various annealing and deposition conditions.

Energy dependence of transport parameters derived from correlated variations in the thermoelectric power and temperature coefficient of resistivity of polycrystalline metal films

Abstract: Literal and general expressions of the thermoelectric power (TEP) of polycrystalline metal films are derived in the framework of the recently proposed three-dimensional model of conduction. Theoretical plots of the thickness dependence of film TEP are given and show that the TEP of infinitely-thick polycrystalline film markedly depends on the grain parameter. These theoretical results, as well as the general relation which expresses the film TEP in terms of the film temperature coefficient of resistivity (TCR), suggest two convenient ways for graphically determining the energy dependence of the bulk mean free path and the Fermi surface area.

Mean free path and effective density of conduction electrons in polycrystalline metal films

Abstract: The thickness dependence of the conductivity of copper, aluminium, silver, gold, nickel and platinum films was measured with high accuracy for various conditions of the evaporation. The Fuchs-Namba model was the only one which could be fitted to the experimental data. Four parameters were determined: σ∞, l ∞, p and h . The ratioσ∞/l∞ is not a constant of the material but depends on the crystallite size. The related effective electron density n ∞ is less than the value n b for bulk single-crystal material. The method employed allows us to separate to volume and surface effects on the conductivity as well as to separate the scattering of electrons inside the crystallites from the reflections of electrons by the crystallite boundaries.

Thermoelectric power of thin polycrystalline metal films in an effective mean free path model

Abstract: Starting from an effective Fuchs-Sondheimer conduction model, the theoretical expression for the thermoelectric power of polycrystalline metal films is derived. From the approximate expression for thick films, a procedure is proposed to determine the variation in the electronic mean free path.

Unexpected size effect in the thermopower of thin-film stripes

Abstract: For low-dimensional materials, size effect of a physical property is usually expected to occur when one (or more) of the dimension sizes decreases to that comparable to or smaller than one of the intrinsic characteristic lengths, e.g., the mean free path. We report here an unexpected size effect, that in centimeter-long stripes of 100-nm-thick metallic thin films, a reduction of the absolute value of thermopower occurs when the stripe width is in the order of 30-50 μm, which is 100–1000 times larger than the intrinsic mean free path of the material. When the stripe width is reduced to 1.5 μm, a relative reduction of thermopower up to 35% is measured in some metals. We suggest that the sidewall scattering due to rough edges of these stripes may be the origin of this unexpected phenomenon. The results may be applied to construct novel thermoelectric devices, such as thermocouples made from a single metal film.

Description of electronic transport properties of monocrystalline films by a statistical model

Abstract: Grain boundaries in monocrystalline films are represented by a two- dimensional array of scatterers. The effects of electronic scattering are calculated by means of Matthiessen's rule starting from the electronic mean free path related to a particular type of scattering (bulk, grain boundary, external surface). Theoretical expressions for the film resistivity and its temperature coefficient of resistivity and thermoelectric power are proposed; comparison with previously reported experiments gives a satisfactory fit.

Mechanisms of adsorbate-induced surface resistivity––experimental and theoretical developments

Abstract: Recent experimental and theoretical developments in explaining adsorbate effects on electronic conduction in metals are critically reviewed. These effects are of more than academic interest, with applications in nanotechnology, chemical sensing, and tribology. The prevailing model treats the metal as a free-electron gas and the adsorbates as independent point scatterers. This model, first developed by Fuchs and Sondheimer and elaborated in recent years by Persson and Volokitin, makes specific quantitative predictions regarding the optical effects of surface resistivity. Some have been accurately verified, including the spectral shape and temperature dependence of the adsorbate-induced reflectance change, and anti-absorption resonances associated with dipole-forbidden vibrations. The model also predicts, however, that the ratio of the adsorbate-induced reflectance and resistivity changes should depend only on the properties of the metal, and not on those of the adsorbate, and this prediction is strongly violated in several recent experiments. Possible explanations of the discrepancy are discussed.