Theory of carrier multiplication factors in the presence of trapping

Abstract
In the presence of trapping, the usual electron and hole ionization coefficients alpha and beta are inadequate to describe the multiplication processes. The usual theory has then to be generalized and four ionization coefficients have to be introduced. The paper shows how this can be achieved and the key results of earlier workers, who assumed no trapping, are obtained as special cases. Some evidence for a trapping effect is seem in low-field ionization measurements.