Chemical resistance properties of molybdenum back electrodes used in non-vacuum Cu(In,Ga)Se2 thin film solar cell

The first step in fabricating copper-indium-gallium-diselenium solar cells (CIGS) is to deposit a thin film of molybdenum (to serve as the back electrode), on a glass substrate. Prior to depositing the absorption layer, the surface of the Mo back electrode is cleaned with acetone; however, this may cause the electrode to separate from the substrate. The aim of this study was to discover the specific cause of the separation, and arrive at a solution to correct this behavior. The result is a thin film comprising crystals of different sizes and orientations. Optimal results were obtained when the bi-layer Mo electrode was deposited on a substrate heated to a temperature of 373 K.

► We discover the Mo electrode to separate from the glass substrate during cleaned process with acetone.
► The bi-layer Mo electrode with substrate temperature of 373 K can block the Mo peeling from glass substrate.
► The acetone diffusion model to compare the possible diffusion paths with different crystallization and texture is shown.