Cross-Section AFM and EFM Examination of Thin-Film Solar Cells

We demonstrated the feasibility of analyzing cross sections of thin-film CdTe/CdS and CIGS/CdS solar cells using atomic force microscopy (AFM). The AFM images were compared with images obtained with the scanning electron microscopy (SEM), and the correspondence was very good. We also used electrostatic force microscopy (EFM) [1] to image the distribution of the electrical potential on cross sections of CdTe/CdS solar cells biased at different conditions. We were able to follow the potential drop at the junction, and the changes in the depletion width for different bias values.