Fundamentals of and Recent Advances in Carrier Selective Passivating Contacts for Silicon Solar Cells

The development of efficient contact schemes curtailing losses due to recombination at directly metalized contacts is the final remaining bottleneck towards approaching the theoretical efficiency limit of silicon solar cells. Given their market domination, the silicon cells demand contact structures that provide passivation of defects at the interface while simultaneously allowing selective extraction of only one type of carrier. Carrier selective contacts are the pivotal research interests to bring about the further advancement of semiconductor solar cells. This review attempts to summarize the elusive classification, fundamental theory and research efforts of carrier selective passivating contact schemes compatible with silicon solar cells. The need for passivation and contact selectivity is identified and the work up to date is comprehensively reviewed. Further, the electrical and optical comparison metrics for these contact schemes are discussed briefly and the challenges to their mainstream PV incorporation are highlighted.