  The analytical modelling of bulk and quantum well solar cells is reviewed.
The analytical approach allows explicit estimates of dominant generation and
recombination mechanisms at work in charge neutral and space charge layers of
the cells. Consistency of the analysis of cell characteristics in the light and
in the dark leaves a single free parameter, which is the mean
Shockley-Read-Hall lifetime. Bulk PIN cells are shown to be inherently
dominated by non-radiative recombination as a result of the doping related
non-radiative fraction of the Shockley injection currents. Quantum well PIN
solar cells on the other hand are shown to operate in the radiative limit as a
result of the dominance of radiative recombination in the space charge region.
These features are exploited using light trapping techniques leading to photon
recycling and reduced radiative recombination. The conclusion is that the
mirror backed quantum well solar cell device features open circuit voltages
determined mainly by the higher bandgap neutral layers, with an absorption
threshold determined by the lower gap quantum well superlattice.
