Origin of Differing Reactivities of Aliphatic Chains on H−Si(111) and Oxide Surfaces with Metal

Abstract

The interaction of deposited metals with monolayer films is critical to the understanding of, and ultimate utility of, the emerging arena of molecular electronics. We present the results of a thorough study of the interaction of vapor-deposited Au and Ag on alkane films attached to Si substrates. Two distinct categories of films are studied: C18 films formed from the hydrosilation reaction of octadecyl trichlorosilane with thin SiO2 layers and C18 films formed from the direct attachment of functionalized alkanes with hydrogen-terminated Si. Two direct attachment chemistries were studied: (Si)3−Si−O−C linkages of 1-octadecanol and octadecanal on H-terminated Si(111) and (Si)3−Si−C linkages of 1-octadecene on H-terminated Si(111). The reactivity of the films was studied with p-polarized backside reflection absorption spectroscopy (pb-RAIRS), sputter depth profiling X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and device electrical tests. Independe...