Reflectance difference spectroscopy - a powerful tool to study adsorption and growth

摘要

Changes in the optical anisotropy of the Cu(110) surface due to adsorption and growth have been studied by reflectance difference spectroscopy (RDS). The optical anisotropy signal at 2.13 eV was found to be extremely sensitive to small quantities of CO, while the signal at 4.3 eV turned out to be particularly sensitive to the transition from a (3 x 1) to a (2 x 1) CO superstructure. In the case of the oxygen covered Cu(1 10), we have successfully monitored and analyzed the transition between two oxygen induced Cu(110) reconstructions: The c(6 x 2)O and the (2 x 1)O phases have clearly distinguishable RDS features, and the transition between them leads to a gradual transformation of the related RDS spectra. For the system Co on Cu(110)(2 x 1)O characteristic features of a CoCuO alloy phase have been identified, which allow to monitor the crucial stages of the Co thin film growth. The alloying and de-alloying are easily recognized with RDS.