The surface-photovoltage diffusion length measurement is analyzed in depth to determine its range of applicability and cause of failure when it no longer yields the diffusion length. It is shown that this technique is generally not valid for amorphous materials, but is highly useful for crystalline semiconductors. The problem of applicability of the surface-photovoltage diffusion length measurement to amorphous materials is not alleviated by using thicker samples or by using chopped light illumination through the back. It is determined that the validity of the surface-photovoltage method requires a density of midgap states <1013 cm−3 eV−1.
Amorphous silicon pin solar cell with a twolayer back electrode Performance and analysis of amorphous silicon pin solar cells made by chemicalvapor deposition from disilane
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.