Time transient reverse current behavior of a-Si:H p-i-n diode

Abstract

When a-Si:H pin diodes are used for medical imaging application, the reverse biased dark current is a sensitive characteristic of diode performance, and the time-transient reverse current behavior may limit the sensitivity and stability of p-i-n diode. Because of defect states within a band gap, reverse current shows a time dependent behavior. We investigate this transient behavior introducing the time dependent electric field, which is originated from the variation of ionized dangling bond density due to trapped charge emission. We assume the components of reverse current are the thermal generation current and the injection current at p-i interface. We also discussed the thermal generation current has a time independent component and a time and bias dependent component. Reverse current transient was calculated using this analytical model and compared with the experimental results.