Date of Award
Department of Physics
Dr. Christos A. Papageorgopoulos
Dr. Lonzy J. Lewis
This study examined the structural and electronic growth properties of the coadsorption of Sodium and elemental Sulfur on Nickel (100) surfaces at room temperature. The investigation was conducted in an ultra high vacuum system using low energy electron diffraction, Auger electron spectroscopy, and work function measurements. The main objective of the study was to create a low work function substrate that would be useful for low work function devices. The research occurred in four stages: (1) adsorption of S on clean Ni(100), (2) adsorption of Na on clean Ni(100), (3) coadsorption of Na on S covered Ni(100), and (4) coadsorption of S on Na covered Ni(100). The measurements obtained suggest that S grows on Ni(100) in a layer by layer mode, forming a p(2x2) initially and a c(2x2) at the completion of the first layer. The second layer of S is disordered. The measurements also indicate that deposition of Na at room temperature forms a single c(2x2) layer. The coadsorption studies showed that the presence of S on the surface of Ni(100) increased the amount of Na that can be deposited on the substrate. A low work function of 0.8eV was obtained during the study. Furthermore, the presence of Na on Ni(100) was found not to affect the deposition of S, however the S was found to destroy the metallic character of the underlying Na.
Mosby_Jr., Dwight L., "Coadsorption of sodium and elemental sulfur on nickel (100) surfaces" (1996). ETD Collection for AUC Robert W. Woodruff Library. 3655.