Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1669020 | Thin Solid Films | 2011 | 6 Pages |
Despite many recent research efforts, the influence of grain boundaries (GBs) on device properties of CuIn1−xGaxSe2 solar cells is still not fully understood Here, we present a microscopic approach to characterizing GBs in polycrystalline CuIn1−xGaxSe2 films with x = 0.33. On samples from the same deposition process we applied methods giving complementary information, i.e., electron backscatter diffraction (EBSD), electron-beam induced current measurements (EBIC), conductive atomic force microscopy (c-AFM), variable-temperature Kelvin probe force microscopy (KPFM), and scanning capacitance microscopy (SCM). By combining EBIC with EBSD, we find a decrease in charge-carrier collection for non-∑3 GBs, while ∑ 3 GBs exhibit no variation with respect to grain interiors. In contrast, a higher conductance of GBs compared to grain interiors was found by c-AFM at low bias and under illumination. By KPFM, we directly measured the band bending at GBs, finding a variation from − 80 up to + 115 mV. Depletion and even inversion at GBs was confirmed by SCM. We comparatively discuss the apparent differences between the results obtained by various microscopic techniques.