EFFECT OF AIR ANNEALING ON THE ELECTRONIC-PROPERTIES OF CDS CU(IN,GA)SE-2 SOLAR-CELLS/

The effect of air annealing on state-of-the-art, solar-cell-quality Cd S/Cu(In,Ga)Se-2 heterojunctions has been studied using contact potenti al difference and surface photovoltage measurements. The annealing tre atment is shown to have no significant effect on the band lineup of th e heterojunction. However, the surface photovoltage spectral response increases markedly upon air annealing. These results can be reconciled if air annealing of the junctions leads mainly to elimination of reco mbination centers, rather than to changes in the built-in voltage or i n the band lineup. We also show that ZnO deposition has an effect on t he surface photovoltage that is similar to that of air annealing.