p-Sexiphenyl/metal interfaces studied by photoemission and metastable atomelectron spectroscopy

p-Sexiphenyl(6P)/metal (Au, Mg) interfaces were studied by ultraviolet phot oemission spectroscopy (UPS), X-ray photoemission spectroscopy (XPS), and m etastable atom electron spectroscopy (MAES). The vacuum level shifts (Delta ) at the interface were observed in both 6P/Au (Delta=-0.8+/-0.1 eV) and 6P /Mg (Delta=-0.4+/-0.1 eV) systems. The MAES spectra indicate that the 6P mo lecules are on the substrate with their mean molecular plane parallel to th e substrate surface in both systems, and that the 6P film on Mg substrate h as some disorder. Thickness dependence of UPS, MAES, and XPS spectra sugges ts no significant chemical interaction for 6P on Au, Mg as well as Au, Mg o n 6P interfaces. In the system of Au on 6P/Au, the spectral feature of 6P i n MAES spectra did not disappear even when the thickness of evaporated gold reached 20 nm, indicating a penetration of Au atoms (or the clusters) into the 6P film. (C) 1999 Elsevier Science B.V. All rights reserved.