Thanks to its good adhesion to glass and a high electrical conductivity, molybdenum is the back contact material in CIGS (copper, indium, gallium, sulphur, selenium) solar cells. However, exposed to corrosive atmospheres molybdenum can be prone to oxidation. Plansee's response: Molybdenum-tantalum.
Pure molybdenum is alloyed with small amounts of corrosion-resistant tantalum, thereby combining the advanced properties of both metals. The superior corrosion resistance of molybdenum-tantalum (MoTa) has been proven in numerous tests. In a corrosion experiment at elevated temperature (60 °C) and high humidity (90%) the carved thin films (layer thickness: 300 nm) of MoTa exhibit a much better corrosion resistance, compared with pure molybdenum.