REVERSE BIAS CURRENTS IN AMORPHOUS-SILICON NIP SENSORS

Measurements are presented of the reverse bias currents in hydrogenate d amorphous silicon nip diode sensors with sizes characteristic of tho se used in two dimensional sensor arrays. Several plates of sensors fr om different depositions were examined. The sensor currents have a com mon low-voltage characteristic due to 'central' leakage currents which scale with the sensor's area. At larger voltages sensors from differe nt depositions exhibit a highly variable excess current which scales w ith peripheral length. We describe transient charge measurements for d istinguishing currents originating from electron/hole generation curre nts and from injection at the n/i and i/p interfaces. It is concluded that the central currents are dominated by generation, and the periphe ral currents by injection.