Abstract
We performed photo-assisted Kelvin probe force microscopy and photothermal atomic force microscopy on Cu（In,Ga）Se2 [CIGS] solar cells to investigate their local photovoltaic properties and photo-carrier dynamics. By means of those techniques, the spatial distribution and temporal decay of photovoltage as well as the nonradiative recombination properties in the CIGS solar cells were examined. As a result, the spatial separation effect of photo-carriers and the contribution of fast process in the whole recombination processes of photocarriers in the CIGS solar cells have been discussed, and the possibility that sub-gap states with discrete energy levels exist in the CIGS material has been pointed out.
