Helium diffraction as a probe of surface topography

Abstract

A brief commentary is presented on the strengths and limitations of various probes of surface structure presently in use. The sensitivity of He diffraction to structure is examined in more detail. The requirements for an open lattice, compared with the scattering cross-section of He, is displayed graphically based on analytical expressions for the He surface potential. The sensitivity argument is highlighted with experimental data as examples. Recent He diffraction studies of open semiconductor surfaces are then specifically discussed to demonstrate the nature of the topographical information which can be extracted.