ELLIPSOMETRIC AND LOW-ENERGY-ELECTRON DIFFRACTION STUDY OF THE LAYER GROWTH OF XENON PHYSISORBED ON AG(111) SURFACE

We have developed an experimental apparatus for in situ observation of a physisorption system on a metal surface by an ellipsometry and an e lectron diffraction. In order to observe a physisorption system and a thick insulator film, we have developed an extremely low-current low e nergy electron diffraction (XLEED) apparatus equipped with a microchan nel plate and a position-sensitive detector in place of a phosphor scr een in an ordinary LEED optics. The ellipsometric adsorption isotherms of Xe/Ag (111) at substrate temperatures between 50 and 80 K were obt ained in the wide pressure range between 10(-7) and 1 Pa. We observed the surface structure by XLEED while monitoring the layer growth by th e ellipsometry from a submonolayer to a thick film where the equilibri um pressure was nearly equal to the bulk saturation vapor pressure. Th e Xe overlayer of a sufficiently thick film has clear (111) structure which keeps relative orientation to the Ag (111) substrate. (C) 1998 A merican Vacuum Society.