Quantum efficiency diffusion length Lq
For planar monocrystalline sheets of Si material, the effective quantum efficiency diffusion length
depends on the diffusion length L of the semiconductor, the back surface recombination velocity Sb, the base thickness Wbas, and the minority carrier diffusion coefficient Dn . The value of LQmono equals the effective current-voltage diffusion length LJ>mono, which determines the dark saturation current density
of a single-sided p-n junction (Eqs. (8) and (9) of Ref. ). The symbol q denotes the elementary charge and nQ is the equilibrium minority carrier concentration. The quantum efficiency can therefore be used to evaluate the amount of recombination in the base of a single-crystalline solar cell [24, 177, 411].
Collection diffusion length Lc The collection diffusion length
for monocrystalline cells is closely related to the collection probability for weakly absorbed light (Eq. 6 in Ref. ). A thin-film cell with base thickness Wbas, diffusion
length L, SRV Sb, and negligible recombination in the emitter would generate exactly the same short-circuit current under spatially homogeneous carrier generation as a semiinfinitely thick monocrystalline cell with a base diffusion length of Lc>mom•