  We report the results of GIXRR, UV-VIS NIR and XPS measurements on Si and Ge
thin films of various thicknesses. While GIXRR measurements show no presence of
oxide on the top of these films, XPS measurements show small amount of oxides.
Also, a sharp increase in surface roughness is seen with thickness in agreement
with the columnar growth of films. In contrast, in case of Si films, oxide is
present even inside the layers but in a very small amount and is not detected
in GIXRR/absorption measurements.
