Molybdenum selenide sublayers with controlled thickness in solar cells and methods for forming the same

A solar cell with a molybdenum back electrode layer and a molybdenum selenide ohmic contact layer over the molybdenum back electrode, is provided. The molybdenum selenide layer includes an accurately controlled thickness. A distinct interface exists between the molybdenum back electrode layer and the molybdenum silicide layer. The molybdenum silicide layer is produced by forming a molybdenum layer or a molybdenum nitride layer or a molybdenum oxide layer over an initially formed molybdenum layer such that an interface exists between the two layers. A selenization and sulfurization process is carried out to selectively convert the molybdenum-containing layer to molybdenum selenide but not the original molybdenum back electrode layer which remains as a molybdenum layer.