A comparative study of Zn(O,S) buffer layers and CIGS solar cells fabricated by CBD, ALD, and sputtering

Zn(O,S) thin films were deposited by chemical bath deposition (CBD), atomic layer deposition, and sputtering. Composition of the films and band gap were measured and found to follow the trends described in the literature. CBD Zn(O,S) parameters were optimized and resulted in an 18.5% efficiency cell that did not require post annealing, light soaking, or an undoped ZnO layer. Promising results were obtained with sputtering. A 13% efficiency cell was obtained for a Zn(O,S) emitter layer deposited with 0.5%O
₂
. With further optimization of process parameters and an analysis of the loss mechanisms, it should be possible to increase the efficiency.