Metal Induced Contact Recombination Measured By Quasi-steady-state Photoluminescence

As silicon solar cells approach limiting efficiencies, recombination at the metal-silicon interface is becoming an important limiting factor. Current methods to characterize this recombination are limited in that either: (1) they can only be applied to test structures that are not representative of the final solar cell; or (2) they require electrical contact to both sides of the p-n junction. In this study, we present a novel measurement technique to study recombination at the metal-silicon interface. The method is based on the quasi-steady-state photoluminescence technique, which is ideally suited because it is contactless and can be applied to completely processed cells with full rear metal coverage, precursor structures or other test structures. The new method is first validated against commonly used open circuit voltage measurements, and then applied to a range of metallized device structures to extract the contact recombination saturation current density.