TRANSIENT SPACE-CHARGE-LIMITED CURRENTS - THE TIME-OF-FLIGHT AND POST-TRANSIT ANALYSIS IN HYDROGENATED AMORPHOUS-SILICON

Abstract

Through evaluation of the post-transit part of the transient space-charge-limited currents (SCLC), it becomes possible to determine the hydrogenated amorphous silicon (a-Si:H) density of localized states (DOS) over a wide range of energies. The use of SCLC conditions results in the enhancement of the occupation of the deep states and hence in the corresponding increase of the signal. In combination with standard SCLC time-of-flight, and since it can be used for both electrons and holes, the method is suitable for the elucidation of the complete DOS distribution, for the examination of the emission times of deep traps, and for the determination of carrier drift mobilities, all on the same p-i-n structure (which may be a standard solar cell).