Size effects in thin gold films: Discrimination between electron-surface and electron-grain boundary scattering by measuring the Hall effect at 4 K

Abstract

We report the Hall effect measured in gold films evaporated onto mica substrates, the samples having an average grain diameter D that ranges between 12 and 174 nm, and a thickness t of approximately 50 nm and 100 nm. The Hall mobility was determined at low temperatures T (4 K ≤ T ≤ 50 K). By tuning the grain size during sample preparation, we discriminate whether the dominant collision mechanism controlling the resistivity of the samples at 4 K is electron-surface or electron-grain boundary scattering, based upon whether the Hall mobility depends linearly on film thickness t or on grain diameter D.

Magnetoresistance of Au films

“…In a previous work, 12 we performed systematic measurements on the temperature and film thickness dependences of the resistivity and concluded that the dominant contributions to the resistivity are from grain boundary scattering and phonon scattering when the average grain size is smaller or comparable to film thickness. This result is consistent with other recent works, 13 which also found that the grain boundary scattering constitutes the most dominant contribution to the resistivity at low temperatures. In the present work, we present detailed measurements of the classical MR of Au films over wide temperature and thickness ranges.…”

Resistivity of thiol-modified gold thin films

“…Unfortunately STM measurements, which could provide a direct number for this parameter, are only possible in flat regions of the films, which are not representative of the density of adsorbed molecules on the "hut" topography. Higher sensitivity of a "hut" type topography in electrical transport of thin films is indeed not a rare occurrence, since it has also been observed in galvanomagnetic transport in gold thin films [28].…”

Research of Conductivity in Polycrystalline Films with a Thin Coating Using the Modified Mayadas–Shatzkes Model

“…In the case of nanocrystalline Co basic films, the size dependences of the specific conductance for the Co films with and without the Ni coating calculated by relations (5) and (6) demonstrate that the deposition of a thin Ni coating results in an increase of their specific conductance (Fig. 3, c).…”

“…In particular, it was shown that the size restriction in films and nanostructures gives rise to the appearance of some physical effects, which are weakly pronounced or not observed at all in massive specimens. As a rule, the surface scattering of charge carriers is described in the framework of the semiclassical approach [6,7]. In so doing, some electrons are supposed to be reflected specularly and the others diffusively by the film surface, with the coefficient of specular reflection from the surface varying from 0 to 1.…”