H2S reaction of Se-capped metallic precursors to form Cu(In,Ga)(S,Se)2 absorber layers

The precursor reaction process for the formation of Cu(In,Ga)(S,Se)₂ (CIGSSe) absorber layers offers great potential for both high efficiency and large scale module production. Nevertheless, long reaction times can create a barrier for cost reduction. In this work, we report on a pathway to a 70 % faster precursor reaction process using a Se-capped metallic precursor. The effects of the precursor reaction time and Se-layer thickness on the through-film Ga- and S-profiles are characterized. These parameters allow control of the band gap profile and the device performance. The process further yields reduced void formation at the Mo/CIGSSe interface and improved adhesion.