Non-linear theory of electrical domains in the presence of trapping

The one-dimensional propagation of stable negative-resistance domains is considered for the case in which the carriers interact with a single type of impurity level. Approximate expressions for the domain velocity and the current in the presence of a domain are obtained for the following cases: (i) Fast trapping - traps in equilibrium with the conduction band at all points in the domain. (ii) Slow trapping: ( a ) Zero trapping - domain moves too quickly for traps to respond. ( b ) Delayed trapping (I) - the high-field plateau is wide enough for traps to respond. ( c ) Delayed trapping (II) - traps in equilibrium with conduction band only above a critical field E c . ( c ) is the case which most closely corresponds to the observed impurity-barrier negative resistance in Ge. The analysis is also relevant to the explanation of slow domains in n-type GaAs.