Investigation of current losses in crystalline silicon solar cells by a new topographical magnetic field technique (CASQ)

Deteriorated areas in solar cells cause current losses. The effects on the efficiency degradation often depend on the external load resistance and the illumination. Since the localization of these shunting areas is essential for further investigations the current flow in solar cells has been studied by a newly developed magnetic field method using a squid sensor (CASQ). We present direct observation of the charge carrier flow for various operation modes. The magnetic field topograms are interpreted using a numerical simulation program for the current distribution in a solar cell. In particular strong deviations from the normal current distribution by local shunts are investigated in detail. Both their positions and electrical I-V behavior could be analyzed.