Dark current in multilayer amorphous selenium x-ray imaging detectors

A theoretical model for describing the bias-dependent transient behavior of dark current in multilayer (n-i-p) amorphous selenium (a-Se) detectors has been developed. The transient dark currents in these detectors are measured and are compared to the proposed dark current model. It has been found that the dark current is mainly controlled by Schottky emission of holes from the metal/a-Se contact. The initial and steady state dark currents are mainly controlled by the barrier height and the trap centers in the n layer, respectively.