The interface between Cu2ZnSnSxSe4−x and molybdenum has been investigated in a detailed model experiment.
The applied TiN layer works as chalcogen barrier but influences morphology and solar cell parameters in a negative way.
Pre-selenized molybdenum as back contact can improve the efficiency.
A novel back contact stack offers a controllable MoSxSe2−x thickness, higher efficiency and reduced variation of the solar cell parameters.