How do As-local structures in CdSexTe1-x respond to bias conditions under (X-ray) illumination?

X-ray microscopy is a powerful tool to study defect chemistry in solar cells since it is capable of probing structure, chemistry, and opto-electrical properties, correlatively, on a pixel-by-pixel basis. In this work, X-ray absorption near edge structure (XANES) was used to probe the As local structures across the depth of the CdSexTe1-x absorber under (x-ray) illumination and bias conditions. It was found that the As structures located near the front contact, which mostly have the spectral features of oxides, are susceptible to undergo structural change under different biasing conditions. While those located near the back contact largely remain unchanged - notably, Cd2AsCl2 and AsTe+Clx complex defect. Additionally, while we found no spectral evidence of the self-compensating AX center, we do observe a high fraction of AsTe+Clx complex around the middle of the absorber, in both low and high performing areas. This finding could explain why a high percentage of the incorporated As is inactive and could perhaps shed light on the self-compensating effect.