2-DIMENSIONAL STRUCTURE AND GROWTH MODE OF ULTRATHIN CE FILM ON MO(110) SURFACE

Adsorbed Ce on a Mo(110) surface was observed by RHEED in order to elucidate the growth mode and the structural change with increasing film thickness. Ce was deposited at room temperature and succeeded by annealing at 800 degrees C under ultrahigh vacuum. The 1st Ce monolayer on Mo(110) surface was composed of a distorted gamma-Ce(111) layer. The second Ce monolayer grew on the 1st Ce layer with the structure of gamma-Ce(111) with no distortion. Further deposition resulted in growth of isolated 3D crystals on the above mentioned Ce double layers. These facts suggest that Ce grows on Mo(110) surface with Stranski-Krastanov growth mode at high temperature (800 degrees C). The first two monolayers as well as the 3D crystals of Ce grew epitaxially, with the Nishiyama-Wassermann orientational relationship of (111)[1 (1) over bar 0]Ce//(110)[001]Mo.