Mo bilayer for thin film photovoltaics revisited

Thin film solar cells based on Cu(In, Ga)Se-2 as an absorber layer use Mo as the back contact. This metal is widely used in research and in industry but despite this, there are only a few published studies on the properties of Mo. Properties such as low resistivity and good adhesion to soda lime glass are hard to obtain at the same time. These properties are dependent on the deposition conditions and are associated with the overall stress state of the film. In this report, a study of the deposition of a Mo bilayer is carried out by analysing first single and then bilayers. The best properties of the bilayer were achieved when the bottom layer was deposited at 10 x 10(-3) mbar with a thickness of 500 nm and the top layer deposited at 1 x 10(-3) mbar with a thickness of 300 nm. The films deposited under these conditions showed good adhesion and a sheet resistivity lower than 0.8 Omega square.