Physical device models: A potential tool in investigating conductivity in ionic and mixed conductors

Extensive work has been done in the last three decades on modelling classical semiconductor devices through physical device models. The majority of these models is based on the simultaneous solution of Poisson's equation, current and continuity equations for electrons and holes using iterative techniques. The vast work done on classical semiconductor devices has been extended to include the study of the motion of charged species upon the application of external fields in insulators, ionic materials, mixed conductors or proton conductors. In this paper the methods used are discussed together with their potential in leading to an understanding of the mechanisms governing charge transport in materials exhibiting more complex conductivity than classical semiconductors.