Étude de la conduction électrique des couches métalliques minces en haute fréquence

The DC and RF resistivity of discontinuous metal films: a size effect theory

“…The fall is because of the AC shunting of islands via gaps (Hirsch andBazian 1964, Deshpande andCrowell 1972). This suggests that high-frequency measurements can give information about metallic conductivity within islands, while DC measurements can give information about the inter-island conduction (Offret and Vodar 1956). Unfortunately no worker has yet tried to extend size effect theory to discontinuous films by HF measurements.…”

Organophosphorus compound detection with a supported copper + cuprous oxide island film. 2. Alternating current studies and sensor performance

“…It has been known since the 1930s that very thin, evaporated metallic films exhibit a decrease in resistance as the frequency of the applied potential increases (3,4). This behavior is physically attributed to the presence of interisland capacitance, whose impedance decreases with increasing frequency (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). In an effort to interpret this phenomenon, the interisland capacitance has been modeled as a continuous distribution (5, 6), as a discrete parameter (7), and as a mixture of the two (8).…”

“…First-order calculations by numerous investigators (9)(10)(11)(12)(13)(14)(15) reveal that a very simple, lumped-parameter equivalent circuit 0003-2700/88/0360-1737$01.50/0 proposed by Chasmar (7) is quite adequate for characterizing measured results. The equivalent circuit is illustrated in Figure 1.…”

“…Most of the impact of NMR in chemical analysis has, until rather recently, been based on NMR signals of species in liquid samples. During the past few years, the advent of such line-narrowing techniques as magic-angle spinning (MAS) has extended the analytical applicability of NMR to a wide range of solid samples (8)(9)(10)(11)(12).…”

“…For cases of isotopically or spatially dilute spin-1/2 nuclides, e.g., 13C, 29Si, 16N, and 31P, the main obstacles to obtaining high-resolution NMR spectra of solids have been inefficient spin-lattice relaxation, dipolar interactions between the dilute nuclei and protons, and chemical shift anisotropy (CSA). These influences are now routinely overcome by cross polarization, high-power proton decoupling, and magic-angle spinning, respectively (8)(9)(10)(11)(12). These same kinds of techniques have also proven to be useful in obtaining relatively sharp NMR peaks from the central transitions of nuclei with n/2 spin, where n is an odd integer, e.g.,27A1 (9,13,14).…”