ABSTRACT
This chapter analyzes ambipolar transport where charge transport rates are linked by an electroneutrality condition. It discusses the effects of relaxation toward charge compensation and the competition between neutralization and recombination of injected charges in semiconductors. The chapter also describes one particular model that is controlled by displacement current. The current density due to electronic carrier transport in a semiconductor or in ionic transport in condensed media is proportional to the thermodynamic driving force. In the drift mechanism, although the electric field tends to accelerate the carriers, they quickly reach a constant velocity because of the presence of resistive forces. Under a gradient of compositions, a displacement of carriers occurs in the lower composition region by diffusion, independent of their charge sign or number. Once the transport distance becomes large and band-bending or spacecharge regions are formed, the variations of conductivity become rather significant to determine transport rates.
