Precursor‐mediated epitaxial growth of GaAs(001) from triethylgallium: Where is the gallium released?

A model is described for the morphological evolution of GaAs(001) during metalorganic molecular‐beam epitaxy (MOMBE) with triethylgallium (TEG) and solid‐As sources. The model includes the migration and attachment/detachment kinetics of atomic Ga and the migration and decomposition kinetics of a more mobile precursor (not necessarily TEG). By biasing the decomposition of the precursor to sites with low coordination, we are able to account for two important observations concerning MOMBE and molecular‐beam epitaxy under nominally the same growth conditions: the reflection high‐energy electron diffraction (RHEED) specular intensity oscillations on a singular surface show higher amplitude and are less damped during MOMBE, but on a vicinal surface, there is no discernible difference in the RHEED measurements for the two techniques.