Effect of exposure of W-D co-deposited films to air on deuterium content in the films

The deuterium loss from W-D co-deposited films after exposure to atmospheric air (-50 % humidity) for 1, 24 and 576 h has been investigated for 50 nm, 250 nm, and 750 nm thick films. Approximately 50 % and 75 % of deuterium is lost after 24 h and after 576 h, respectively. The rate of deuterium loss is similar for thin and thick films. Significant amount of protium is trapped from air during exposure, which releases in H2 and H2O during thermal desorption spectroscopy analysis. Even after 24 days in air, the films do not transform into tungsten oxide.