Picosecond Processes in Carrier Transport Theory

Abstract

High electric field transport has been studied for some three decades. In recent years, it has become of much greater interest due to the advent of semiconductor devices on the micron and submicron scale, and to the interaction of these devices with sub-picosecond optical pulses. Theoretically, hot-electron transport (as this high-field transport is usually called) has been traditionally discussed in terms of the Boltzmann Transport Equation (BTE). However, semiconductor transport in these high electric fields is a classical example of carrier response described by far-from-equilibrium thermodynamics. More importantly, on the short time scale of the response of these devices, particularly to the short optical pulses, retardation of the carrier dynamics must be fully considered. Such retardation does not appear in any dynamical description based upon the BTE, and more exact formulations must be adopted.