AVS 45th International Symposium
    Surface Science Division Monday Sessions
       Session SS-MoP

Paper SS-MoP20
The Study on Activated Chemisorption on Surface of La Thin Film

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Surface Science Division Poster Session
Presenter: S.M. Shao, Nankai University, China
Authors: S.M. Shao, Nankai University, China
W. Qian, Nankai University, China
J.P. Song, Nankai University, China
S.L. Li, Nankai University, China
Z.Q. Zhuo, Nankai University, China
G.K. Xi, Nankai University, China
Correspondent: Click to Email
The surface characteristics of evaporated rare-earth metal La thin film were studied by ex-situ and in-situ AES and molecular beam techniques. In case 1, the La thin film was prepared in the vacuum system, then taken out of the system exposing under atmospheric condition and finally put into the UHV chamber to be studied. In case 2, the La thin film was prepared and in-situ studied in the UHV chamber. The surface composition by ex-situ AES studies corresponds to mainly La(OH)@sub 3@ which can be attributed to a surface modification by O@sub 2@ and water vapor from the ambient atmosphere. The in-situ AES studies reveals the surface composition of La. The activated chemisorption of CH@sub 4@ on La thin film was studied in both cases using molecular beam technique.@footnote 1,2@ After surface cleaning treatment of samples, chemisorption probability was measured as a function of translational kinetic energy. The initial sticking probability was found to depend strongly on the incident kinetic energy E,scaling E@sub n@=Ecos@super 2@@theta@@sub i@. The initial sticking probability increases linearly with the translational kinetic energy of the incident molecular beam, but the threshold value and the activated energy were not changed when the surface temperature was increased from 500 K to 700 K.} @FootnoteText@ @Footnote 1@ G. Xi et al., J. Vac. Sci. Technol., A9(3),1688(1991) @Footnote 2@ S. Shao et. al., Chinese Vac.Sci. Technol.,12(2/3),263(1992)