Estudio comparativo de la adsorción de S sobre Au(111) y Ag(111) con XPS, AES, TOF-DRS y LEED

Abstract

Here we study the adsorption of S on the (111) Surface of the noble metals Au and Ag using XPS, AES, LEED and TOF-DRS. Despite the similarities of the two surfaces, all the techniques showed different behaviours in both surfaces from the beginning of the adsorption. XPS and AES were used to determine the dependence of the S coverage with dosing time, whereas LEED allowed us to identify the ordered phases of the S/Au and S/Ag systems. The S coverage in Ag grows continuously with dose, while for Au there is saturation of the S signals in q ~ 0.5ML. Analysis of the intensity and shape of the TOF-DRS signals provide evidence about the coexistence of Ag atoms with S atoms in the top most layer for all coverages, whereas in Au these effects can be discarded up to q ~ 0.3ML.