Growth layer for photovoltaic applications

A substrate bearing a stack of layers as the back contact in a molybdenum photovoltaic device, said back contact comprising in order from the substrate:

• a barrier layer;
• a layer of ZnO;
• and
• a layer of molybdenum, wherein the molybdenum is deposited directly on the layer of ZnO;
• the ZnO layer having a thickness, t, of 0 nm<t<50 nm;
• wherein the ZnO layer is deposited directly on the barrier layer;
• and
• the barrier layer comprises at least one of:
• SnO2, SiCO and TiO2.

A method of controlling the crystal orientation of a molybdenum layer on a substrate comprising the steps of:

• depositing a barrier layer comprising at least one of:
• SixNy, SiO2, SnO2, SiCO and TiO2 on the substrate,
• depositing a primer layer comprising TiO2 or ZnSnOx directly on the barrier layer,
• depositing a layer of ZnO directly on the primer layer, and
• depositing a layer of molybdenum directly on the layer of ZnO;
• wherein a thickness, t, for the ZnO layer is selected according to the desired crystal orientation wherein 0 nm<t<50 nm.