Nano- and Micro-scale Defect Analysis in CuInSe2 Solar Cells with Ag and K Incorporation  
Tara Nietzold1, Michael Stueckelberger1,2, Trumann Walker1, Nicholas Valdes3, Bradley M. West1,4, Barry Lai5, William N. Shafarman3, Mariana I. Bertoni1
1Arizona State University, Tempe, AZ, United States
/2Deutsches Elektronen-Synchrotron, Hamburg, Germany
/3University of Delaware, Newark, DE, United States
/4Boston Fusion Corp., Lexington, MA, United States
/5Advanced Photon Source, Argonne National Laboratory, Argonne, IL, United States

Multi-scale characterization is used to evaluate the impacts of Ag-alloying and KF-post-deposition treatment (PDT) on CuInSe2 solar cells. Nano-X-ray fluorescence measurements show an almost 5x higher AAC ratio for ACIS compared to ACIS+KF. The increase in Ag concentration is found particularly near the CdS surface and may serve as a limitation to the potential benefit of Ag-alloying. X-ray beam induced voltage (XBIV) signal is enhanced with the use of KF-PDT. Photoluminescence shows reduced non-radiative recombination with KF-PDT and increased bandgap near the CdS interface from Ag-alloying. KF-PDT has a stronger relationship to increased performance than Ag-alloying.