Thermally Stimulated Exoelectron Emission (TSEE) and ESCA Study of Au and Ni Exposed to Ar, O2, N2 and C2H5OH Vapor Plasmas

Abstract

The interactions of Au with Ar and O2 plasmas, and of Ni with O2, N2 and C2H5OH vapor plasmas have been studied by TSEE and XPS. The TSEE was strongly influenced by the amount of oxygen incorporated at metal surfaces due to the effects of the plasmas, and was suppressed by the oxygen incorporated in excess. With Au samples, Ar plasma produced a TSEE peak at about 170°C and O2 plasma two peaks at about 180–190°C and 120°C; O2 plasma gave a much weaker emission than the Ar plasma. Au samples exposed to the plasmas gave XPS spectra of Au, C, O, Al and Si. The incorporation of Si and Al may be attributable to the plasma reactor. The TSEE was closely correlated with the composition ratio of O/Si, resulting in a maximum at the value of O/Si=0.4. With Ni samples, a TSEE peak appeared at about 177°C independently of the plasma atmospheres. The peak intensity was satisfactorily correlated with the ratios of O/Ni and O/C, giving a maximum at the values of O/Ni=8 and O/C=1.