Reflection high-energy electron diffraction intensity oscillation study of Ga desorption from molecular beam epitaxially grown AlxGa1−xAs

Abstract

Reflection high‐energy electron diffraction (RHEED) intensity oscillations are used as an in situ probe to study Ga desorption during molecular beam epitaxial growth of Al_xGa_1−xAs. A simple thermodynamic model is developed which, in the limit of low As₄ : group III beam flux ratios, accurately predicts the measured changes in Al_xGa_1−xAs growth rate and composition due to Ga desorption at elevated growth temperatures. The desorbing Ga flux is observed to be less in thin epitaxial layers of GaAs growing on top of AlGaAs than in bulk GaAs, giving rise to a growth rate transient at heterointerfaces.