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 cm(2)/Vs and are weakly temperature-dependent from 100-300 K. These values are lower than the range of electron Hall mobilities (2-1100 cm(2)/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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3692165]