Date of Award


Degree Type


University or Center

Clark Atlanta University(CAU)

Degree Name





This study examined the adsorption of elemental S onclean Si(lOO) surfaces and Cs on s- covered Si(lOO) surfaces. The study was performed in an UHV system using LEED, AES and WF measurements. The objective was the protection of the\ surface against degradation. The s adsorption process may be enhanced by the addition of Cs. Results indicate that S adsortion forms: a hemisulfide, (~0.5 ML) with a (2xl) structure and a monosulfide, (~1 ML) with a (lxl) structure. Adsorption of Cs on clean Si(100)2xl reduces the WF to a minimum value with a subsequent increase towards the value of metallic Cs. Preadsorption of Son Si(100)2xl lowers the WF to a final plateau without the increase. The presence of S increases the binding energy and the maximum amount of Cs that can be deposited on the Si(lOO) surface. Structural models for S and Cs on Si(lOO) surfaces have been given in the text.


Signature pages on file with the graduate school. An archival copy of the document is available in the Archives Research Center.

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