Experimental determination of local-bonding configuration at the early stages of growth of the heterogeneous Pt/InP(110) interface by synchrotron-radiation spectroscopy

The interaction of Pt adatoms with the InP(110) cleaved surface for coverages between 0.1 and 6 monolayers (ML) is studied to explore the chemical-bonding configuration at the early stages of formation of the interface. The Pt/InP(110) interface is heterogeneous: a dominant reacted Pt-P phase forms on patches of surface and grows in depth; traces of other Pt minority environments are observed; regions of the InP surface remain unreacted; and In is segregated. The Cooper-minimum photoemission method, using synchrotron radiation as the photon source, is employed to obtain indicators of the partial density of states of Pt 5d character and P 3sp character of the Pt-P dominant reacted phase. Core-level synchrotron-radiation photoelectron spectroscopy (Pt 4f, In 4d, P 2p) and P L2,3VV Auger line-shape results are also presented. The bonding structure between Pt and P at the interface formed by 3 and 6 monolayers of Pt on InP(110) is reminiscent of the Pt silicides.