Intrinsic secondary ion emission from binary alloys during Ar+ bombardment

Abstract

The emission of positive atomic secondary ions from single phase binary alloys during 15 keV Ar+ bombardment was studied in an ultrahigh vacuum environment. For all the five alloy systems: Fe–Ni, Cu–Ni, Pd–Ni, Al–Ni, and Si–Ni, the ionization probabilities of the elements show little or no correlation with the bulk alloy density of states or the local density of states near the Fermi level. When the ionization probabilities are compared with the electronegativity differences of the elements, we notice that only the emission of Al+ and Ni+ from Al–Ni alloys seems to follow the direction of the anticipated charge transfer.