Fig. 5

Phase variations on standard CIGS solar cell. a, b Intensity line profiles showing the phase variations (green line) which are extracted from the regions marked in Fig. 4a, b. Below, the intensity profiles that are extracted from the same regions in the HAADF-STEM image (yellow lines) are shown. In order to correct for residual background gradients in the phase images, an individual linear background was subtracted from each phase variation line profile. The relative thickness variation, measured by HAADF-STEM (I _HAADF-STEM) and the absolute thickness variation, measured by the phase images (\(t_{\text {phase}}\)) based on a, b, are given in c, d. The corresponding EDX profiles are depicted in e, f showing relative concentration variations. The copper signal in the ZnO region originates from stray electrons that impinge on the copper grid. Further a significant amount of Mg and O is measured in the CIGS region. These are artifacts due to the overlap of the Se L-lines with the K-lines of Mg and the Cr L-lines (Cr is present in the TEM specimen holder) with the O K-lines. In addition to the EDX profiles of the present elements, also the relative variation of GGI and CGI is qualitatively shown in the graph