Characteristics of lithium thin films under deuterium ion implantation

To clarify characteristics of thin Li films as a plasma facing material, effect of modification of chemical composition of μm-thick deposited Li films introduced during the sample preparation and implantation with 1-keV deuterons on deuterium retention and thermal desorption properties is studied. Accelerator analysis has been employed to measure the thickness, the retention of D, H, O and C in the Li film, while thermal desorption spectroscopy has been utilized to investigate the chemical composition. The Li films exposed to moist atmosphere and subjected to D implantation show almost perfect isotope exchange from LiOH to LiOD. Carbon deposition during ion implantation is found to form a layer mixed with Li. With increasing the deposited amount of C, D2 desorption behavior approaches that of pure C.