GROWTH MODE AND TEMPERATURE-DEPENDENT MORPHOLOGY OF INDIUM ON GAP(110)

The growth of indium layers on cleaved GaP(110) surfaces has been studied by core- and valence-level photoelectron spectroscopy, in order to elucidate the growth mode and morphology of such layers. In order to provide a basis for the analysis of the metal-covered surface, the surface core-level shifts of the clean GaP(110) surface have been characterized in detail. We find a three-dimensional growth mode (indium clusters) at room temperature, whereas low-temperature deposition leads to a kinetically limited (Poisson-type) quasi-laminar growth. Metallic in clusters and a Fermi edge were identified at coverages as low as 0.5 monolayers. Line-shape analysis of the In4d and Ga3d levels shows that the interface exhibits weak reactivity, both at room and low temperature. Annealing of indium layers deposited at low temperatures, however, leads to the appearance of a reacted indium component. These data are discussed in comparison with the behaviour of other metal overlayers on compound semiconductor surfaces.