Observation of intensity oscillations in rheed during the epitaxial growth of Cu and fcc Fe on Cu(100)

Abstract

Oscillations in the intensity of the specular beam in reflection high energy electron diffraction (RHEED) have been observed during the epitaxial growth of Cu on Cu(100) and face-centered cubic (fcc) Fe on fcc Fe. These oscillations are not observed in the initial stages of growth of Fe on Cu(100). Thus it is inferred that the homo-epitaxial growth of both metals is by a Frank-van der Merwe (layer-by-layer) mechanism but that the hetero-epitaxial growth of fcc Fe on Cu(100) is accompanied by strong agglomeration of the first Fe monolayer followed by gradual burying of the Cu substrate. This burying is complete after approximately 5 ML at 255 K. In addition to facilitating the determination of the active growth mechanism, these experimental results allow for a simple, effective means for calibrating the incident metal flux from the MBE vapor sources.