Using reverse bias currents to differentiate between bulk degradation and interfacial degradation in hydrogenated amorphous silicon p-i-n structures

Abstract

The ‘‘analysis of microelectronic and photonic structures’’ (amps) transport-simulation computer program has been used to show that a distinction can be made between the effects of light-induced bulk and interfacial degradation in hydrogenated amorphous silicon (a-Si:H) p-i-n detector and solar cell structures. Using reverse bias leakage (dark) currents, amps simulations show that, for p and n layers that do not allow significant injection of electrons and holes into the intrinsic layer of the p-i-n structure, a light-induced increase in the density of interfacial states will result in significantly different changes in the voltage behavior of the reverse bias dark currents than will a corresponding increase in the density of bulk defect states. This communication demonstrates that a careful study of the reverse bias dark currents can provide an excellent means of determining if light soaking of a-Si:H p-i-n devices results in bulk degradation, interfacial degradation, or both.