Evidence of palladium phosphide formation at the Pd/InP(110) interface

The bonding in the reactive Pd/InP(110) interface at room temperature has been investigated by valence-band and core-level photoemission in conjunction with photon-induced Auger spectroscopy. A dramatic change of the spectra identical to those previously reported for the Pd/Si interface strongly indicates formation of a stable palladium phosphide, most probably ${\mathrm{Pd}}_3$P, at the interface in the Pd coverage range from ∼ 2.5 to ∼ 15 monolayers. It is suggested that such transition-metal-P compound formation may be a general phenomenon for transition metals on InP and other III-V compounds.