ZnS Nanodot Film as Defect Passivation Layer for Cu(In,Ga)(S,Se)2 Thin‐Film Solar Cells Deposited by Spray‐ILGAR (Ion‐Layer Gas Reaction)

Wurtzite-phase ZnS nanodot films with controllable dot density can be prepared at low temperature by a technique known as Spray-ILGAR (ILGAR = ion-layer gas reaction), without organic surfactant. ZnS nanodots covered with homogenous In2S3 (as the point-contact bridge) act as a defect passivation layer and form a structured buffer layer. This ZnS/In2S3 buffer improves cell efficiencies by up to about 1%–1.5% compared to reference cells with a pure ILGAR In2S3 buffer.