ABSTRACT
An ensemble of carriers in equilibrium follows Fermi-Dirac statistics. In equilibrium, randomly oriented velocity vectors or associated mean free paths (mfps) in vector addition give a zero vector sum. The application of an electric eld tends to align these tiny electric diploes in the direction of an electric eld. In this chapter, nonequilibrium Arora distribution function (NEADF) is discussed [1,2]. NEADF is an anisotropic distribution function that is an outgrowth of the isotropic Fermi-Dirac distribution function. The velocity-eld proles briey discussed in Chapter 3 are microscopically analyzed as randomly oriented velocity vectors streamline in the direction of an electric eld making the velocity unidirectional in an extremely high electric eld. This is the source of ultimate saturation of velocity vectors.
