Growth processes in molecular beam expitaxy of single‐crystal Al layers on AlAs

The molecular beam epitaxial growth processes of Al single‐crystal layers deposited at room temperature on As‐stabilized and on Al‐stabilized AlAs surfaces are investigated in situ using reflection high‐energy electron diffraction (RHEED). The epitaxy relationship of Al with the underlying AlAs is (011)[100]Al//(001)[110]AlAs irrespective of the surface stoichiometry of AlAs. Detailed RHEED investigation suggests that the initially deposited two one‐monolayer‐thick Al layers form a sphalerite lattice on As‐(Al‐)stabilized AlAs with the same lattice spacing as AlAs, while the deposition of additional Al layers induces the structural phase transition from the sphalerite lattice to an fcc lattice with bulk Al lattice constant. Thick epitaxial Al layers show (4×1) surface reconstruction.