Analysis of (Ag,Cu)(In,Ga)Se2 solar cells deposited by a hybrid process

(Ag,Cu)(In,Ga)Se₂ (ACIGS) thin films were deposited using a hybrid process combining reactive dc sputtering (Cu, In, Ga) and thermal evaporation (Se) and then processed for complete PV devices. Efficiencies as high as 12.6% (without MgF₂ AR coating) were obtained. Performance of these devices were analyzed and compared with evaporated CIGS solar cells with equivalent band gap. Our analysis shows that the reason for the lower efficiency of these devices compared to evaporated CIGS (of equivalent Eg) may be attributed to the low Voc¬ associated with a low FF. XRD, SEM and SIMS analysis seems to indicate a strong influence of the crystal orientation on the efficiency as well as the compositional distribution of the elements (with lower Cu and Ag at the interface with CdS) that may lead to a lower quality junction, and therefore enhanced recombination.