We have investigated the effect of exposure to thermal Sn atoms on the 13.5-nm specular reflectivity of single-layer Pd mirror surfaces. The mirror surfaces were characterized using low-energy ion scattering spectroscopy (LEISS) and the relative 13.5-nm specular reflectivity measured in situ during exposure to doses up to several 1016 cm-2 Sn particles. The relative reflectivity loss at 13.5 nm is found to deviate from the theoretical Fresnel reflectivity. Losses are <∈20% for fluence levels >∈1016 cm-2. The difference is due to deposited Sn nucleating at early stages of exposure and coalescing to nanoscale islands. Sn atomic surface fraction from LEISS reaches 50∈a/o (atomic percent) at a fluence of 0.25×1016 cm-2 and ultimately levels off at 93-95% for fluences greater than 2.0×1016 cm-2. The specular reflectivity approaches the Fresnel theoretical value of 38.7% for thermal Sn deposition at large doses and equilibrates to 36.4%. The difference is mainly due to surface roughness of the deposited Sn film.
|Original language||English (US)|
|Number of pages||4|
|Journal||Applied Physics A: Materials Science and Processing|
|State||Published - Apr 1 2008|
All Science Journal Classification (ASJC) codes
- Materials Science(all)