Photovoltaic characterization of Cu(InGa)Se2 and Cu(InAl)Se2 solar cells by photoassisted Kelvin probe force microscopy

We observed photovoltage as well as potential distribution around grain boundaries (GBs) in thin film solar cells based on Cu(InGa)Se
₂
(CIGS) and Cu(InAl) Se
₂
(CIAS) materials by the photoassisted Kelvin probe force microscopy (P-KFM) method we have originally proposed. As a result, the abrupt drop of the potential and the enhancement of photovoltage around the GBs was observed on both CIGS and CIAS materials. We also found that the typical value of the photovoltage on the CIAS solar cell was apparently higher than that on the CIGS cell.