Effect of CdS deposition temperature for thermally grown Cu(In,Ga)Se2 and two-step chalcogenized Cu(In,Ga)(S,Se)2 absorbers on solar cell performances

CdS layer deposited at a low temperature was thinner and therefore probably included many open voids where CdS/CIGS junction was degraded. The junction interface was greatly improved by increasing the deposition temperature because CdS was thick enough to cover the whole surface of the absorber. Void depth in the CdS layer grown at a low temperature did not significantly change by increasing the deposition duration. The CdS/CIGS solar cell efficiencies were strongly correlated with the void depth and total thickness of CdS, which was determined by the deposition temperature.