ARSENIC CAPPING AND DECAPPING OF INYAL1-YAS(100) GROWN BY MOLECULAR-BEAM EPITAXY

A study of the surface of InyAl1-yAs, grown lattice matched on InP(100 ) by molecular beam epitaxy, protected by an As cap during storage in air and subsequently annealed in ultrahigh vacuum. is presented. The s urface structure and stoichiometry of the layers are investigated by l ow energy electron diffraction and x-ray photoemission spectroscopy. T hese investigations show that decapping may be achieved by annealing t he sample at 390-degrees-C to reveal an atomically clean, As-stabilize d surface, exhibiting a (3 X 1) symmetry. It is also shown that the re lative population of In and Al on or near the surface is different fro m that of the underlying bulk InyAl1-yAs layer and that the overall su rface symmetry and stoichiometry may be further adapted by annealing t o higher temperatures.