Effective diffusion lengths for minority carriers in solar cells as determined from internal quantum efficiency analysis

We introduce a general relationship between the effective diffusion length L-Q of solar cells derived from spectral quantum efficiency Q and the effective diffusion length L-J that determines the saturation current j(0)=qn(0)D/L-J of the diode in the dark. The general relation L(Q)greater than or equal to L-J holds in the presence of grain boundaries and of spatially nonhomogeneous doping profiles. We find the relation L-Q=L-J for solar cells without potential fluctuations at the collecting junction. (C) 1999 American Institute of Physics. [S0021-8979(99)01707-7].