The impact of front contact ZnO:Al/Zn1‐xMgxO layer on Cu(In,Ga)Se₂ thin‐film solar cells

We studied the impact of the front‐window layer on Cu(In,Ga)Se 2 (CIGS) solar cells. A bi‐layer structure of ZnO:Al/ZnO was used as a standard front‐window layer, and a replacement of ZnO by Zn 1‐x Mg x O was analyzed. A numerical simulation was performed to understand the device characterization results. The results clearly indicate that any variation on the front‐window layer and deposition condition impacts the underlying CdS/CIGS junction. Therefore, it is important to carefully choose the component of the front‐window layer and sputtering parameters to protect the junction formation. With careful front‐window layer design and modeling, an optimized device performance with a Zn 1‐x Mg x O layer has been achieved (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)