ON THE IMPACT OF ELECTRON SPECTROSCOPIES (VERSUS OPTICAL TECHNIQUES) TO STUDY ORGANIZED ORGANIC LAYERS AND THEIR INTERFACES

When preparing and characterizing ordered organic layers, knowledge of the structure of the ultra-thin films is often missing or difficult t o gather. For different self-assembled layers of the thiol and carboxy lic acid families, we show that this valuable type of information is o btainable with X-ray photoelectron spectroscopy (XPS) and high-resolut ion electron energy-loss spectroscopy (HREELS). Indeed, information on the film order and superficial composition is available through analy sis of the core-level peak positions and widths (in XPS), and through study of the elastic peak width and angular distribution and analysis of the material excitation function (in HREELS). However, for some ins ight into the crystallinity of the layer and intermolecular interactio ns, infrared spectroscopy in the grazing-angle absorption-reflection m ode (IRAS) appears to be complementary. (C) 1998 Elsevier Science B.V.