Modeling of effects of material quality on fast characterization of state-of-the-art a-Si:H p+–i–n+ diodes

Abstract High-quality amorphous silicon p+–i–n+ diodes have very small dark leakage currents, allowing the detection of low intensity illuminations with a dynamic range of several orders of magnitude. Low currents imply that a change in the charging state of the device may take very long times, up to a few minutes. A correct current as a function of voltage measurement becomes time-consuming. We discuss and model the effects of the density of defects in intrinsic material on such measurements. The model takes into account Poole–Frenkel thermal generation currents and the rearranging of the equilibrium generation rates to explain the observed negative offset in the voltage at which zero current is measured in a fast measurement. The offset is related to the density of defects and the study, comparing model and experimental data, shows an approach to quickly evaluate the quality of the device with no need for a full time steady state measurements.