Some New Techniques in Reflection High Energy Electron Diffraction (RHEED) Application to Surface Structure Studies

Abstract

A new apparatus for reflection high energy electron diffraction (RHEED) provided with an electron gun with a sharply focused electron beam and operated under ultrahigh vacuum condition has been constructed. It has a specially devised fluorescent screen which enables us to take new type RHEED patterns corresponding to sections of the reciprocal lattice rods and similar to LEED patterns. The oscillating- and the rotating-crystal methods have been applied to observe the intensity distributions along the reciprocal lattice rods. On the basis of experimental results obtained in the studies of the Si(111)7×7, Si(111)√19×√19 Ni and Si(111)5×1 Au structures, it is concluded that the RHEED method including the new technique is superior in principle for the surface structure research to LEED almost in all respects. It is expected that RHEED will find wide applications in the field of surface research taking the place of LEED.