Electron drift-mobility measurements in polycrystalline CuIn1−xGaxSe2 solar cells

We report photocarrier time-of-flight measurements of electron drift mobilities for the p-type CuIn1−xGaxSe2 films incorporated in solar cells. The electron mobilities range from 0.02 to 0.05 cm2/Vs and are weakly temperature-dependent from 100–300 K. These values are lower than the range of electron Hall mobilities (2-1100 cm2/Vs) reported for n-type polycrystalline thin films and single crystals. We propose that the electron drift mobilities are properties of disorder-induced mobility edges and discuss how this disorder could increase cell efficiencies.