%0 Journal Article %J IEEE Trans. Electron Devices (USA) %D 1980 %T The superposition principle for homojunction solar cells %A Tarr, N G %A Pulfrey, D L %K carrier lifetime;carrier mobility;solar cells; %P 771 - 6 %V ED-27 %X The assumption that the quasi-Fermi levels are constant across the depletion region of a forward-biased, illuminated cell, is examined in detail. It is found that the quasi-Fermi levels do, in fact, vary significantly across the depletion region of an illuminated cell operated at short-circuit or low forward bias. However, it is shown that if the carrier mobilities are reasonably high and the carrier lifetimes reasonably long, the superposition principle still provides an excellent description of the cell characteristics at all bias levels. The superposition principle may seriously overestimate the efficiency of cells fabricated on poor-quality substrates with very short lifetimes and low mobilities %Z superposition principle;homojunction solar cells;depletion region;carrier lifetimes;quasi Fermi levels;carrier mobility; %9 article