Tracking Se Local Structures Across CdSeTe Absorber with X-ray Microscopy

X-ray microscopy is a powerful tool to study defects in solar cells as it allows to correlate pixel-by-pixel the local environment of selected atoms and the nanoscale electrical performance. In this work, we used X-ray absorption near edge structures (XANES) and X-ray induced current (XBIC) to track Se local structures, particularly changes in Se-Cd bond lengths, across the CdSexTe(1-x) absorber layer, and contrasts areas with high and low electrical performance. Even though all the experimental Se K-edge XANES clearly show signature of CdSexTe(1-x), there are spectral changes both across the absorber, and at different performing areas, revealing different atomic surrounding of Se atoms which together with XANES at the As K-edge may provide a full picture of the role of defects in the bulk's electrical performance.