Question

The origin of contact noise?

Answer 1

theory of contact noise is described in which the low-frequency noise is attributed to the random movement of adsorbed ions on the surface of a semiconductor from which an electron current is being drawn. Emission of electrons is assumed to take place only at localized patches on the surface and the adsorbed ions are assumed to give rise to a Schottky barrier layer, in which the potential maximum is linearly related to the concentration of ions. Diffusion of the ions over the surface gives rise to random fluctuations in the concentration of ions in a patch which results in random fluctuations in the height of the potential barrier and the emission current. It is shown that for a circular patch the spectral power density of the noise current varies with mean current J0 and frequency f as j02fx over a small range of frequency and that x varies monotonically from -0.75 at the lowest frequencies to -1.125 at the highest frequencies. It is also shown that for a long thin rectangular patch in index x varies monotonically from -0.5 to -1.5 as the frequency is increased from zero. The dependence of the noise power density on temperature

Answer 2

• An experiment of squeal noise on a lubricated elastomer/glass contact is presented. The experimental device, stiff enough to be known.