Temperature effect during atomic layer deposition of zinc oxysulfide -Zn(O,S) buffer layers on Cu(In,Ga)(S,Se)2 synthesized by co-evaporation and electro-deposition techniques

In this study, we investigate the performances of Cu(In,Ga)(S,Se)₂/Zn(O,S) devices varying both the absorber and the deposition temperature of the atomic layer deposited Zn(O,S) buffer layer. For both types of devices, two ranges of Zn(O,S) deposition temperatures were found to improve significantly the opto-electronic parameters, due to either specific Zn(O,S) properties or interdiffusion mechanisms. With this approach, we demonstrated the existence of two distinct favorable band alignments at the CIGS/Zn(O,S) junction. This study also demonstrates the benefits of using Atomic layer Deposition to accurately control the Zn(O,S) properties and therefore avoid device annealing and i-ZnO replacement by (Zn,Mg)O window layer.