  A quite general device analysis method that allows the direct evaluation of
optical and recombination losses in crystalline silicon (c-Si)-based solar
cells has been developed. By applying this technique, the optical and physical
limiting factors of the state-of-the-art solar cells with ~20% efficiencies
have been revealed. In the established method, the carrier loss mechanisms are
characterized from the external quantum efficiency (EQE) analysis with very low
computational cost. In particular, the EQE analyses of textured c-Si solar
cells are implemented by employing the experimental reflectance spectra
obtained directly from the actual devices while using flat optical models
without any fitting parameters. We find that the developed method provides
almost perfect fitting to EQE spectra reported for various textured c-Si solar
cells, including c-Si heterojunction solar cells, a dopant-free c-Si solar cell
with a MoOx layer, and an n-type passivated emitter with rear locally diffused
(PERL) solar cell. The modeling of the recombination loss further allows the
extraction of the minority carrier diffusion length and surface recombination
velocity from the EQE analysis. Based on the EQE analysis results, the carrier
loss mechanisms in different types of c-Si solar cells are discussed.
