No abstract

Drift-current-pulses in semiconductors with vanishing dark conductivity measured according to the method of Kepler and LeBlanc deviate from the expected rectangular pulse shape even under ideal experimental conditions. In this work it will be shown that among other processes the diffusion of current carriers is responsible for the deviation. Under appropriate experimental conditions one is able to measure diffusion-constants in anthracene by a method to be described. Within experimental error the diffusion-constant obtained agrees with the value calculated from the Einsteinrelation using the independently measured drift-mobility. The differences in method from the known techniques used with dark conducting semiconductors are discussed. The measurements succeed only with very good crystals for which quality criteria are given.