In this paper we discuss and model the effects of the
density of defects in hydrogenated amorphous silicon from an electronics
point of view. To this end, we have created a SPICE model that accounts for
the two main field effects, Poole-Frenkel and tunnel, responsible for the
leakage current. The comparison between our model and the experimental data
shows that our approach allows a quick evaluation of the quality of the
device with no need to run a complete steady state measurement. Also, we
have validated our SPICE photodiode model by implementing it into a three
CMOS simple pixel structure.