The Semiclassical Charge Transport Model and Its Extension to Organic Semiconductors

Abstract

AbstractThis chapter develops the semiclassical charge transport theory that describes the movement of electrons and holes in a semiconductor. We will start the discussion by understanding different charge transport modeling approaches. These include the quantum mechanical approach, semiclassical particle approach, and semiclassical ensemble approach. We develop the charge transport equations using the ensemble approach. Starting with the Boltzmann transport equation, we derive the drift–diffusion model that describes charge transport in semiconductors. Subsequently, we will discuss the boundary conditions that are essential to describe charge transport phenomena at interfaces in an optoelectronic device. The boundary conditions discussed include ideal contacts, non-idea contacts and their parameters—surface recombination velocities, contact resistance, ideal non-contact boundaries, and surface exciton generation at non-contact boundaries. Equal weightage is given to the mathematical formulation and physical interpretation of the boundary conditions. We then discuss the validity of the semiclassical charge transport model. Finally, we highlight important aspects central to charge transport in organic semiconductors.