| Abstract: | Adsorption of bismuth on gold thin films is studied by electrical resistance variations. At low coverage the increase of gold resistivity due to Bi adatoms is 2.3 ± 0.1 μΩ cm/at% and is independent of temperature and thickness of the Au layers. At 20° C and ?150°C, the shape of the resistance variation curve for increasing Bi coverage indicates that the adatoms form a first monolayer having a higher density at lower temperature. At 85°C two Bi monolayers are made successively: the first is adsorbed on the free surface of the gold film; the second grows on the other face, between the gold and the glass substrate, after migration of the Bi atoms through the grain boundaries or other defects. These results are verified by Auger electron spectroscopy. They are used to show that the initial reflectivities for conduction electrons on the two surfaces are similar in recrystallized gold films; the specularity coefficients P and Q have been evaluated using the Fuchs theory. For clean surface, the electron reflection is large specular (P ? Q ? 0.75 ± 0.05) and becomes entirely diffuse when a monolayer of bismuth is adsorbed on each face of the gold film. |
