Synchrotron-based characterization of solar cell nanodefects

It is accepted throughout the photovoltaic community that the overall performance of entire modules is regulated by inhomogeneously distributed nanoscale defects inside the wafers. Over the years a variety of techniques have been used to map and characterize precipitates, grain boundaries and dislocations. However, in the race to achieve higher and higher resolutions, while studying industry-relevant material, many of these techniques fall short either due to the inherent resolution limitations of the equipment or because the combination of low defect spatial densities and strong heterogeneity, present a challenge to sample preparation and characterization. In this work, we discuss the future of synchrotron-based nanoprobe techniques for identifying defects in large volumes of commercial solar cell materials. We describe a state-of-the-art X-ray Fluorescence (XRF) nanoprobe beamline to identify the precise nature of performance-limiting defects in commercial mc-Si solar cells. For the first time, XRF with a beam spot size < 100 nm is used to characterize the contamination levels in solar cell materials.