Photoemission oscillations during epitaxial growth.

We report the use of in situ, near-threshold photoemission to study the dynamics of GaAs surfaces during epitaxial crystal growth and, in particular, the observation of oscillations in the photoemitted current. These oscillations are found to depend upon the growth rate in the same manner as do reflecting high-energy electron diffraction intensity oscillations, occurring at the monolayer accumulation rate. We believe that they depend upon a cyclical variation in the step edge density on the growing surface and discuss the mechanism through which the oscillatory current may result from surface states or surface dipoles. [ABSTRACT FROM AUTHOR]