Interpretation of reflection high-energy electron dfifraction oscillation phase

摘要

The use of reflection hgih energy electorn diffraction (RHEED0 became very popular after te discovery of reflected electron beam intensity oscillations in the early 1980s. Although a number of theoretical explanations of the effect have already been given, many asects of he question as to why RHEED oscilations appear still remains open. We propose a enw mechanism which may lea to the appearance of RHEED oscillations. This mechanism can be briefly described as kth periodic variaiton of diffraction peak postions due to changes in the average scattering potential near the crystal wurfce during the depositionof a enw laeyr. We concldue that in a generla cae one can explain qualitatively the origin of RHEED oscillations as the superposition of effects due to: (1) periodic variaions in surface roughness, (2) changes in intererence conditions for waves scattred from different surface terraces and (3) periodic variaotns in he aveerage potential in the topmost layer.