Abstract
The surface morphology of molecular-beam-epitaxy-grown GaAs(001) has been investigated using in situ scanning tunneling microscopy and reflection high-energy electron diffraction. Films grown on nominally flat substrates at very slow growth rates display a multilevel system of terraces elongated along [11̄0], suggesting an edge energy anisotropy of the order of 10:1 and a preference for sticking at B-type steps.