Noise in Microstructures

Noise in devices is due to local random events, namely scattering mechanisms undergone by the carriers, which produce fluctuations of the current flow, and hence fluctuations of the voltage at the ends of the device. The knowledge of the noise is important mainly for two reasons: From a fundamental point of view, it gives information concerning the transport mechanisms (basic limitations such as the scattering mechanisms with phonons, etc., or technological limitations due to impurities, defects, etc.); from an applied point of view, noise is a fundamental limitation to the sensitivity of the device, so that it is important to study whether it can be lowered or not.